My suggestions...

I'm no motherboard expert, but I'd go with a 1.1 AMD Duron, maybe a 1.2, depending on price....and a motherboard with the VIA KT266A chipset (did I get that chip number right, guys?) Don't get the 266...has to be 266A. They really optimized the memory controller between the two releases, and the 'A' is way faster. You could go with a lower end motherboard, but this chipset will allow you to upgrade to an Athlon XP later on, if you decide you want to.

As far as video card....well, you could get just about any GeForce 2. Considering the GF3 has been out for a while now, they're really coming down in price.

A couple more things. One of the biggest bottlenecks in a lot of modern computers is the hard drive. Don't buy a Maxtor, and don't get a 5400RPM. Spend the extra, and get a 7200RPM Seagate, IBM, or Western Digital.
I've got a 486DX4-100 with a 7200RPM Seagate 20GB drive, and you can really tell the difference between that and a 5400, even with that slow old processor. I've done image analysis on that system that we normally do on a PIII-933. Yes, it was a heck of a lot slower, but it did it. And loading images from the HD wasn't much slower at all.

As far as anything to avoid like the plague....let's see....some people would disagree with me, but I'd say name brand systems...Compaq, Dell, IBM.
Also, if you're wanting this to be an economy PC, don't even look at Intel.