Unless you have a 64-bit operating system you might as well limit your memory to 3GB of RAM, because 32-bit versions of Windows only recognizeup to 3GB (that may be an oversimplification--you can Google "/3GB switch" if you want to know more). When I bought my computer in late 2005 I maxed out my motherboard with 4GB of RAM, and bought Windows XP Professional x64 Edition to be able to use all that RAM effectively. The problem with a 64-bit OS is that the drivers are not as mature (especially the sound card drivers). If you've got Vista, however, it typically comes with both the 64-bit and 32-bit install disks packaged together in the same box, so you can install the 32-bit version first, and then after the drivers have been improved, you can do a clean install of the 64-bit version (unfortunately installing the 64-bit version requires a clean install, but the Vista install disk knows how to do this--just make sure you back up all your important files first).

I have dual GeForce 7800GTX 512 cards in SLI. nVidia finally has a set of drivers that will support Quad-SLI with my OS, Windows XP Professional x64 Edition, so I could grab a pair of the the GeForce 7950 GX2 cards, however, Quad-SLI is still not optimized, and it wouldn't make much sense for me to rush out and buy new graphics cards now with DirectX 10 right around the corner. I am kind of jealous of those ATI users who can play Oblivion with both HDR and AA enabled at the same time, however, I'm sure I'll be able to buy new nVidia cards within a year that can do that. If I wanted to switch to ATI I would need a new motherboard, besides which, there is no Quad-CrossFire yet, and SLI is simply a more mature technology.

Prior to 2003 or 2004, Intel was definitely the way to go for a gaming CPU. Maybe it will be once again. And although raw clock speeds don't always measure performance, I wonder if we ever will see a 4 or 5 GHz CPU from Intel or AMD, and how long it will take. Based on the trend in the late nineties and early 2000's, you'd think we would have already gotten there a couple of years ago.

I basically look at the performance reviews at various sites dedicated to computers and PC gaming hardware. Then I save my money and get the most powerful thing I can afford that will work with my current system. Some games run better on nVidia and some on ATI, however. And ATI and nVidia are continually outdoing each other, but SLI is a better and more mature technology than Crossfire, so if you want to use multiple cards it makes more sense to go with nVidia SLI.