Thanks in part to your help and advice, I am now enjoying the wondrous sounds of vinyl. I expected the music to sound good and warm, but wasn't expecting the additional excitement of putting the record on the player, lowering the arm, watching it spin, etc. Also new is a budding interest in bossa nova, 70's rock, soul, and a renewed love of the Grateful Dead. I'm truly thrilled.

As is my pattern, when I "finish" one project, I ponder the next. So there you have it, my reason for this post.

I'm wondering what you might suggest as a way to improve the sound quality. My system as it stands right now is:
Marantz SR8000 receiver
Parasound Zphono Preamp
Pioneer PL-115d II
And I forgot the name of the cartridge, but the local audio store told me it was a good match for the player and didn't hint at selling me a new one.
NHT 1.8's (and soon 1.5i's!)
Fancier RCA cables and fat gauge speaker wire.

(I love to read rants and raves so feel free to drop your best audiophile humor on my so called "system)

Obviously not head turning stuff, but good for the (little) amount of money I put into it.

If I wanted to put about $200 to $300 into a sound upgrade (used is fine), where would you put it?

For example:
A new stand for the turntable to replace the rinky dink Ikea table?
A heavier carpet for the floor?
More Wall hangings or some acoustic panels?
Thick curtains or drapes?
Record cleaner?
A fine bottle of wine?
Cotton swabs for my ears?

I'd love to know your thoughts.

Enjoy the Super Bowl.

TT stand or
Record cleaning machine
I second the TT Stand. You can buy or build a good one that can be used with your next TT as well. You may not notice any big sound improvement, but it will feel good. Especially, if you build it. There are many posts and preferences on this subject.
Put it in your 401K.
Best Upgrade is always the one in better Designer brain. The BBFB* Upgrade without any doubt is the Bottle of Wine. A lot of Systems are only bearable drunken. But after a while it can be dangerous when the liver gets into clipping all the time ...

* Best Bang For Buck
Buy more vinyl.
not being sure how many records you have, a RCM could be a great investment. See if you can find a good used vpi 16.
If you go for the RCM, then I second a used VPI 16. I've had mine for more than twenty-five years. Noisy, like a vacuum, but works great and still supported.
The fastest and easiest record cleaner that also does a good job is Spin Clean. I eventually added a VPI but still use the SC for the first step to get all of fuzz, dust and finger prints off. Sometimes I get lazy and skip the 3 more steps on the VPI.

later when you want to get fancy add a vac machine.
I just acquired the $80 Spin-Clean manual record washing system and am amazed at the results. I did throw together a separate vacuum system made from an old Dirt Devil portable and a notched crevice tool with some velvet strips. That speeds up the process to the point where I can clean 15 records or more in a one hour session. LPs I've owned fort 30 or 35 years don't quite sound new again but darn close to it. An isolation platform to go on my turntable shelf is next . Also spent $5 on a couple of 12" square thick concrete pavers to go under the speakers and was surprised that the difference, although subtle, was audible. Ditto the results from a homemade composite cork and leather turntable mat to replace the thick rubber one that was stock with my Technics SL-1400. All these changes have cost me a total of less than $150 yet have actually made a difference that I can hear.
Buy yourself a Radioshack SPL meter for $50.00 and down load REW at Home Theater Shack (free) and do some measurements. Learn what your system is really doing. Then add some acoustic panel and see how much better your system will sound. Dollar for dollar the best money you can spend on any system.
Mount it on the wall, save your money, add another few to it...then buy a used Rega.
The dinky dink Ikea table I think your turntable is probably sitting on - Lack? Corras? - is actually pretty well regarded by a lot of turntable guys. Leave it alone for a while IMO.

I'll go with a lot of the previous posts and suggest a vacuum cleaner. I use a KAB USA EV-1 and a hand held steam cleaner. The KAB was about $170 and the steamer was about $30 or so. There's nothing like a good clean album. If its not squeaky clean, it doesn't matter what gear you're running.

The cleaning matters even more if you've got old vinyl that's been sitting around and/or you're buying used stuff from local shops or garage sales.

Other than that, get more albums, beverages, and time to enjoy your music. After you've got a lot more disposable money, then start upgrading. Not that this stuff has to be expensive by any means. There is some great gear out there for not a ton of cash, regardless of what some people here may tell you.