Building a new computer

[Jonbo298]

I'd recommend getting PC2700 RAM. It's faster then PC2100 and if you look around, PC2700 are sometimes the same price as PC2100. Or if you have the money to just spend, get PC3200. Since I'm guessing your mobo is pretty new, it should be able to handle it. Also, could I have a link to the mobo you're getting? I'd like to see the specs.
Also, your video card will be able to handle Doom3/HL2. You got to think, when they started Doom, the GeForce FX wasn't even close to being out. But if Doom3 was started just recently, it might need the more high end cards. But don't feel nervous that yours might not. It will.
When I got my mobo a month or 2 ago, it came with 2 built in USB2 ports. And 4 more that I just plug into on the mobo and just use an extra slot on the back for 4 more USB2 ports. So it shouldn't even be expensive to have USB2 ports.
I can't help you much on the sound issue because thats one area I'm not very knowledgeable when building a comp. I just like as much power as I can afford/get.