I'm looking for a big new LCD or projection type

flat screen TV....

Here are my choice:

1. SAMSUNG HLT5687 56in DLP Projection HDTV...1080P, contrast ratio 2500:1....'Very sharp flat screen TV when compare to Sony SXRD 60in.(KDS60000).

2. Sony SXRD KS60000 60in. ...DLP, 1080P, contrast ratio 10000:1 etc.

3. Sharp Aquos LC52D82U 52in. LCD flat screen....1080P, contrast ratio 10000:1 etc.

4. Sharp Aquos LC52D62U 52in. ....1080P, contrast ratio 1500:1 etc.

Which one is a better choice ???

I'd go with the Samsung.

IMHO, unless you're viewing from the sweet spot (i.e. directly in front of the tv) all the time, I would go with one of the LCD's.
You see that contrast ratio number? That needs to be a high as you can get, I would suggest Sony....you get what you pay for. We bought a Samsung unit a few years ago and I know things have changed but that TV was noisy to the point we had to take it back...we love our Sony.
Yeah, well I love my Samsung :). Just kidding, but I think the bigger choice here is the choice between LCD and DLP. Off axis viewing of DLP is unacceptable to me.
The Sony is SXRD not DLP.
I dont think DLP is the way to go, it is the cheap way to go but it is on its way out....folks want flat, and if we are trying to get the best sound...we need flat, slim, and ideally on the wall.
a friend works at a TV shop in town & suggests DLP or CRT over plasma, LCD etc that is unless you want something thin/narrow etc.

He also prefers Mitsu Diamond series over the more expensive Sony stuff

Most of the high end stores here in town also prefer diamond series over the more expensive sony stuff
The Sony SXRD XBR2 is far superior to the Mitsubishi. It uses three separate chips and no color wheel. It's a big TV, (wide and deep) but the picture is beautiful. It's available in either 60" or 70" sizes. More expensive than the Mits but clearly superior even to the new Mits models that have just arrived in stores. The Mitsubishi's are nice TV's and represent an incredible value in relation to the size TV you get for the money. Also the mid-level model is a much better value than the Diamond line as it incorporates the Dark Detailer shutter that increases black level. Diamond line has the shutter but beyone that you're paying mostly for convenience and cosmetic upgrades.

That said you should definitely look at the just arriving Mitsubishi LCD flat panels. Available in 40", 46" and 52" sizes. I've only seen the 40" entry level model with a Philips BluRay playing the Discovery Channel Planet Earth disc at 1080p. The picture was as detailed and sharp as any I've seen and had that elusive 3D quality. Like with the DLP's the mid-level model represents the best performance/value as it adds 120Hz refresh and a fourth front accessible HDMI input. Might be a couple of weeks before they're all available in stores.
I think Sony is the way to go. The SXRD is close to LCD except way off axis, but better than anyone else's DLP, especially the XBR SXRD mentioned above, in my opinion. If you want an LCD, get a Sony Bravia - there really isn't anything out there that touches it, so far. The new Sonys are adding the 120hz refresh to the Bravias and also to the top SXRD.

Looks like I will be getting the KDS-Z70XBR5 when it comes out in a month or so. I need the screen size and the 72" Sony LCD is apx $30K. From all indications, the new SXRD is supposed to be pretty close in picture quality to the 72" LCD but at a much more reasonable price. I currently have a KDL-46XBR3 Sony LCD in my office and the picture is just incredible.
From what I've seen, I believe plasma still has a more movie like picture quality, now closely followed by LCD and then the sony SXDR and I-dla and then DLP sets. Sixth Ave. Electronics in NJ (rt.4) has been clearing out panasonic plasmas (older models) and even the new panasonic 58inch 1920X1080 plasma can be had for less than $4,000 if you haggle. I'd look at plasma first and then the high 4ms refresh rate LCD's from sony,sharp and samsung. Ultimately, the picture quality will depend on the source.
Every Sony I SXRD I have seen are eye-catching but ultimately unnacceptable out of the box. They come with the color levels cranked way up. Just look at scene taken in a lush green forest. But wear your sunglasses. I have seen a couple of ones that that have been adjusted. Those were much better. Take a look at the new JVC I-DLA. I haven't seen one yet but they are getting great reviews for their picture quality. Supposedly they are one of the rare TVs that have true colors out of the box. And they are only 11" deep. This is an RPTV. Apparently shallow RPTVs are on their way. The one complaint with the JVC is the linear distortion on the edges. The reviewers don't seem too upset by it, but I haven't seen it. That is the result of the shallow depth. Though there is a technology coming on that is suppose to correct for all of this. Add in laser or LED bulbs and I am pretty excited. Next year, maybe. Plasma has burn-in and reliability issues. Though from most reports done right it blows away LCD. I am not sure. Pretty much every Plasma I have seen looks more like an over produced poster than a photo. DLP has the color engine, though LED illumination gets rid of that and LCDs aren't big enough yet. Of course, the real problem with almost all of them is that they are set at the factory way over the top for color. And your big box stores just leave them that way. So how do tell how good they can look. Drives me crazy when I go into the stores. Most of the TVs on display are horrible. At least that is my take on it.
You should check out Vizio P50HDTV. 50" Plasma. I am not a plasma fan, but I bought one! Multiple inputs and 1080i and will only set you back about $1,400. View it in theater mode and you will see what it is capable of. Out of the box it is not great, but I used the custom settings from the Sound and Vision review and it is hard to justify spending more. IMHO
Just got another Sony KLD-46xbr, this time an xbr4, which is the latest 1 that just came out (my house got jealous of my office). This new TV sets the new standard and I've noticed it's even a little better for watching sports, probably due to some tech improvements. People who have seen the set immediately ask where I got it and how much it cost. Retail is around 3500 but it can be found online for a lot less. That would be my recommendation - if you can swing the funds, why "settle" for something less?
NEW 1080p 58 inch. flat panel LCD from Panasonic or new 1080p Samsung 47 inch.LCD with 15000:1. These would be my choices in 4 large price range. New 47 inch LCD 1080p from Vazio or Westinghouse if your are on tight budget.
I would wait and do a bit more research on the LED backlit LCD. You want a high contrast ratio? How's about 500,00.00:1 ?. DLP will eventually go away except a few big size like 72" or 73". The retail price of these dinosaurs has dropped drastically and so is the retail price of the Plasma. Some company as Toshiba has stopped making the DLP. Mits still have some 65" to 73" DLPs untill their Laser tvs debut.
We have the Aquos LC52D62U and are delighted with it. There are some better spec numbers out there but the 'D62U looked better than anything we saw at a large Best Buy store with the exception of a couple of super big Pioneers in the $7500 - $12,000 range which impressed me as "equal" picture quality as the Aquos. Our in home experience with this TV has been as impressive as was our showroom experience...Ultimately, I suspect the individual preference factor for these devices is quite similar to that with higher end loudspeakers - what impresses one may not be as impressive to another. I'd have a look at each of these units you're considering in person and up next to one another if possible. As with audio, what's visually most "musical" to you may or may not depend upon spec. numbers so much as what the experience provided in real time is like.
Samsung is best banmg for buck (you pay bit of premium for Sony's nice styling).I'd go for any of fist 3.See the reviews at CNET and PC World.
I would go with the Sony because it has a great picture and it's bigger. 52" to 60" is a pretty large jump and I think having a larger picture adds a lot to the enjoyment. Of course you don't say what your distance is, or if you need a flat panel (I don't). Someone else mentioned the new Mits DLP units which are also worth considering (again not flat but up to 73".)
Best bang for the buck - Sony KDS-60A3000. Lists at $2200 - 60" and should be viewed before you purchase anything. It rivals and surpasses a number of LCDs and plasmas in picture quality at 1/2 to 1/3 the price. One of the best-kept secrets in video that I recently got turned onto.