The Mainboard is a critical component. Unfortunately, it's also one of the most confusing pieces for the novice builder. There's some that work only for Celerons, some that work for Celerons and Pentiums, but only up to a certain speed, some that work for new AMDs, some that work only on Tuesdays with old Cyrix processors...you get the idea...
Unfortunately, Athlons and Pentiums require different motherboards, which means you can't mix and match.
Why not one of the newer, fancier motherboards that support DDR RAM and other
gizmos? Because those things are expensive. Expensive toys should be played
with AFTER you've got a solid rig up and running.
Thus, the A7V from Asus, one of the most respected motherboard manufacturers
and one of the most popular boards FROM one of the most respected motherboard
manufacturers. Why emphasize herd mentality? Because it's easier that way.
Asking for help regarding a board everyone has gets better results. Asking for
help for an unknown motherboard lives you sitting alone and all sad and lonely.
It features AGP support, 3 DIMM slots for maximum upgradability, and enough PCI
slots to fit in all your cool cards (and then some!). For those of you wanting
to get into overclocking, it's rumored to be good for that, too. You want
solid? One review site reports that it's incredibly hard to crash. What's that
mean? 36 hours straight, intensive load, no crash. Sounds like it'll outlast
ANY serious Unreal Tournament marathon.
If you decide to go Pentium, you have more choices in motherboards. Kind of. There's the i820 chipset, which is supposed to be revolutionary, but has had a ton of problems. Then there's a whole series of prior chipsets. While new i820s might be flawless, there's always that stench of failure hanging over them. So we reach back to that bastion of knowledge (a.k.a. "The Last Guide") and continue with the ASUS CUSL2-C which is based on the i815 chipset. While it may be behind the cutting edge, it's also less inclined to be buggy, failure ridden, or otherwise problematic. We value stability over maximum performance.
This board will support up to the PIII 1GHz, if you have the cash for an upgrade in the future. You can put up to 512 MB of RAM in this bad boy, put in 6 PCI cards, and play with the 2 USB slots in the back. In short, this is perfect for future upgrades and for putting in all those nifty cards right now.