Looking for suggestions on reasonable upgrades

upgrade the turntable

you can find some nice deals around $800 used

Agree with the above. I can also testify to the quality of Frank's cables. I have both the interconnects as well as the speaker cables. I've compared them to MUCH more expensive cables (MIT Terminator 2, Sonoran Desert Signature, etc.) and they simply cannot be beat for the money.

The rest of your system actually looks great and very well-balanced. I'd like to hear it. My father uses the original Thiel CS 3s and I think they're fantastic. I bet that NYAL really keeps them under control!

I agree with the above comments. Get Frank's cables (Signal Cable) and you will be amazed without spending much money. The Monster Cable has GOT to go.

IMO, you should consider dumping the old Monster Cable speaker cable and get something that is newer and not oxidized. Old Monster Cable is very dark and cloudy sounding.

Here is one approach: get the most out of what you have, then upgrade depending on the weakest link in your system, a different playback medium, etc.
By getting the most out of your system, I mean take care of the little things, manage vibrations, adress the power issue, use good cables. Exactly what you do about vibration, power, or cables depends on your budget. Keeps these enhancement items in line with your overall budget (20%). Look to AudiogoN for power chords and cables, look for quality wall recepticles, brass spikes, do the little things like keeping cables off the carpet, cleaning your records and routing cables away from one another.