Help me deceide on pre-amp please

I'm looking for suggestions on my next upgrade. I'm leaning towards a new pre-amp. Perhaps a VTL 2.5 or maybe a Audio Research unit. I'd prefer to keep the price under $1500 USED.
A friend of mine was kind enough to let me try a Cal Aud Labs Sigma Dac on the O/P of my NAD and I did like the tube effect. It was not a huge improvement IMO but did add a certain bloom and impact on the upper bass and lower midrange. It was this audition that has convinced me to include tubes in my search but I am open to suggestions on both SS and Tubed units.
Ideally the preamp will have remote volume and HT pass as I plan to integrate this into a HT sys. I listen to mostly pop and rock music.

Here is my current 2CH sys.

NAD C542 CD Player
Aragon 8008ST Power Amplifier
Acurus RS-11 Pre-amplifier

Paradigm Reference Studio 100 V3 Loudspeakers
Paradigm Servo 15 V2 Subwoofer
Rogue Audio Magnum 99 line stage.Used goes around your price range and perhaps less.Great sonics IMO,a favorite among audiophiles.Solid aluminum housing remote "brick type"and HT bypass can be added at factory.Can't go wrong with Rogue.
I have a VTL 5.5 and am very pleased with it. (Power amp is Krell 2250 driving N804's, sometimes Thiel 3.5's and currently Wilson Benesch for a few weeks.) Bass control is quite good. Also, it has some great features. There is a used one at Upscale Audio for about $1,800. Depending on how your room is set up, you would likely experience a noticeable difference. (I have no affiliation w/Upscale.)
If you can up your budget just a bit, you would be very happy with this:

It has everything you are looking for, including HT pass through and an excellent Headroom headphone amp, is built like a tank, and would hang in there sonically if you continue to upgrade other parts of your system. This pre was rated Stereophile Class A. It should work wonders with the Aragon, and without sacrificing your bass extension and detail. Disclaimer; I own it and yes, this is a sales offer, but also true IMHO.
I would second the Rogue 99. I use it both for two channel and to power the l/r for home theater. You really don't need an ht bypass. Just use your line outs from your ht receiver into one of the 99 inputs and find a volume setting on the 99 that is to your liking and use the ht receiver for the volume control for all speakers.
The Linar Audio Pre 2 is very tube like in sound but rare on the used market. As well as the Edge G series pre amp.
First verify that the input impedance of your Argon is 50K or greater. If so, buy an Audio Research SP16 (used if possible). On the used market these will be priced around $1500 - $1600.
Sonic frontiers Line 2
I concur with the Rogue suggestion; I'm using Rogue Magnum 66 and enjoy it. I found I preferred the sound of the 66 to the Audio Research LS-9 (a solid state unit). You can find a Magnum 66 for about $700. There are two different versions: Line stage (with remote, no phono), and phono (without remote).
An additional nice feature is internally switchable tape output can be made into second main out - nice for biamping. I don't know if this can be done with the Rogue 99.
I have my HT set up similar to Yohjo suggests. Works great.
Another vote for the Rogue 99 Magnum.
I was looking with interest at the Rogues and in particular the 66 that is on here now. The only problem is that during my research I found that they have a very spotty history as far as reviews both prof and user goes.
If you are considering tube pre-amps you should have conrad johnson on your short list. I believe a used premier 14 is close to your budget.

I purchased a new VTL 2.5 a few months ago and am very pleased. It has HT bypass and a remote for volume and mute only. I got some NOS Mullards from Upscale Audio to replace the 2 12AU7 and 2 12AT7 standard tubes - will cost you about $150 for all 4 tubes and you could buy a used 2.5 for $1000-$1200. This combo will give you the midrange bloom as well as great detail and presence.
I'm using an Aragon amp(4004MKII), too, and it's a good match in impedance and performance. They also look good together - the VTL comes in either silver or black. I'm not selling anything, just a fan.
I'd stretch a couple of hundred and find a VTL 5.5. This is a top tier preamp. Whatever preamp you buy it is always not a bad idea to run the serial number through the MFR to find out its history. VTL can give you this info on the phone for most of their products. Some of their early stuff was prePC and not in their database. Both the 2.5 and 5.5 will be.

I would suggest you avoid tubed preamps with a lot of tubes in them as they can get Very Expensive to upgrade/replace when required.
Thanks for the great suggestions?
Any more?
dehavilland. Here is the link to a demo. (I still vote for the VTL 5.5. Of course only your vote counts!)
C123666, I used to think the tube cost was bad, but after researching and playing with the SF preamps, I found only two of the tubes made most of the difference compared to stock tubes. For example, the SF Line 2 and Line 1 only take 6 tubes each, and could achieve excellent sound with 2 NOS 7308's or 6022's at $100/pair, and 4 low noise new tubes at $20-30/pair. The Line 2 was rated a Stereophile Class A preamp using the stock Sovtek 6922's at $12 each. Buyers should also check the product's reputation for how hard the equipment is on tubes, since they last longer in some of the preamp designs. Partsconnexion says Pearl Tube Coolers can increase tube life (we shall see). To me, adding a tubed pre was worth it for the improved body and dimensionality in the sound of my system.