And my 3c :P
Currently the best card to get is 8800GTS with 320MB of RAM. They are fast, cheap to buy and have a future design - DX10.
But, if you're a cheap bastard, like me, and play mostly LOMAC, like me, you'll get the classifieds out and get a used X1900XT or pro /X1950XT and if you're nVidia orientated, 7900GTO/GTX or 7950GT . People are dumping them, like they're already garbage. I've got myself X1900XT for half the price of a new one. I don't regret it a bit. I went for ATI, just because of shadow problems in LOMAC, no other reason. Play's everything maxed out on a whooping 1920x1200 resolution. It's a bomb of a card. And when this idiotic frenzy around DX10 dies down a little, get yourself a nice middle range DX10 card for half the price people are paying now (or a used 8800GTS 640MB if you're a cheap bastard like me, whooop :)
For the rest of the machine, i'd recommend getting the same stuff everybody's buying right now - E6300 or E6400, at least 2GB of DDR2 RAM, preferably a 800MHz one, so you can overclock if you ever feel like it, and a good mobo, maybe Asus P5B-Deluxe or equivalent.
And in time, when you've saved some money, get a projector, or even better, build one yourself and you'll be pretty much LOMAC nirvana :pilotfly: