GeForce 6600GT

I've heard that this is the best "cheap" card around, but I was wondering if anyone could recommend a good brand to buy.

eVGA makes the reference cards for nVidia. I have one of their PCI-E 6600GT cards, and it's the best bang-for-the-buck right now.

get whatever the cheapest one you can find is that has:
a. the refrence/stock eVga type heatsink(msi's ones are fine too)
b. 128 bit memory

as long as it has both of those, your good to go. you can probably get one from newegg for about $140-50 right now

I got an eVGA for 145 with a 10 dollar rebate. It plays CS:S on all max/no AA and KOTOR2 all max everything. I clocked it to 350/1000. It's a decent investment, in my opinion, as long as you don't plan on upgrading to PCI-E if you get the AGP version (I did- fuck PCI-E.)

I bought an MSI PCI-Ex16 128MB 6600GT for $178 a little while ago, and it works well enough.  It's also a hell of a lot cheaper than the 6800/7800 lines.