There's been a lot of stuff going on.
-ATi and nVIDIA released their new cards NV40 and R420. (6800 and x800)
The 6800 GT is the best deal out there right now. Very close is the x800 pro, but doesn't have support for DX 9.0c and SM 3.0. Best right now is X800 XTPE but is very closely followed by the 6800 Ultra and will probably take the second place when SM 3.0 and DX 9.0c really gets into use.
-Socket 939 came out. It's not worth it yet. I suggest waiting for PCI-E mobos and DDR 2.
-PCI-E is very close. Not too big of a deal, but you can do SLI (two cards, each rendering one part of the screen) which would boost performance incredibly. Too bad it would cost incredibly much.
-DDR 2 is also close... well not close, it's out, but good luck trying to find a motherboard.
-Razer's back in business with a new kick *** gaming mouse -- The Razer Viper
-New LCD monitors with 12ms are the new thing... perfect for gaming... and emptying out your wallet
-Doom 3 will be out soon, so you need to upgrade. The Nvidia vid cards are slightly better than ATI. A64 is better than P4 in gaming.
-New chipset for the A64 Socket 754 is out -- nforce 3 250
-Water cooling is getting much more common in everyday rigs
-Intel's Prescotts's are hot as hell. I mean that literally. Don't even consider one unless you have water cooling
-New A64's like tighter memory timings, while P4 are fine with looser ones
-As said above, PC3200 is getting kind of like a minimum. The higher, the better, especially with those crazy P4's with phase change cooling that get up to 4GHz and above 250 FSB!
-9800 pro is/was a really good deal out there until the new generation cards came out. It's still a good deal, but it's really tempting to get a 6800 NU for around $60-80 more
-There's many good cases out there (Cooler Master CM Stacker, ThermalTake Tsunami, etc.)
-I could keep going on and on, but I think I'll stop here and let you figure out the rest on your own