Cheap tweaks...What would YOU reccomend?

I like the homemade room lenses and rollerblocks a lot.
My best tweek in antistatic spray on my whole system. Interconnects, speaker cables, power cables, plc, ics inside the components, wires inside the components etc. The improvements include a bigger soundstage, crisper dynamics, and reduced glare/brightness.

You could get a copy of Robert Harley's book, "The Complete Guide To High-End Audio". Lots of good information in there.

If you haven't replaced your receptacles at the wall (or in your line conditioner if you have one), I'd strongly recommend the Arrow Hart 8200 (available for about $8 U.S.) If you have two or 3 receptacles that your system is drawing from, this will make a very worthwhile improvement to sound quality. I also like the vibrapods (bear in mind that I have a relatively modest system and we are talking about "cheap" tweaks) and use them under both electronics and speakers (floorstanders). If you have a budget CD player, you might want to experiment with damping the interior of the casing (commercial industrial floor tile attached with double sided heavy duty carpet tape works well); I've had good results doing this. All of these are sub $20-$25 tweaks ( a little more if you start piling on the vibrapods), which I figure is pretty cheap.

Morasp:
Do you have any particular brand preference for the antistatic spray?Thks

The best and cheapest tweak you can do is speaker placement. Experiment with moving your speakers away from the back and side wall. Aiming them to face in front of you or behind you. If you have floor standing speakers lifting them off the floor a few inches can make a considerable difference.