Thank you Melinda. Now that you mention it, I remember Tiger from my "Computer Shopper" days (back when it was about as thick as a phonebook).
One thing about Tiger is that when you click on the motherboard you are interested in they will put a list of compatible components on the right side of the screen. The two systems I built weren't monster gamers or anything but I didn't need that. My FIC motherboard has three memory slots that accept 1GB each. It's very expandable and only cost $59. I put a 2.0GB Celeron processor on it and a 64MB Radeon AGP graphics card with support for the new DVI LCD monitor cables. The total system, case, power supply, DVD drive, CD Writer, hard drive, memory, and graphics card ran me about $450 or less. I used the Ultra 2100 memory. One thing I regret in a way is that I only put a 20GB hard drive in it. I wish I had put at least a 40. If you already have some components you should be able to get a really good motherboard and the rest of your parts at the price you want to spend at Tiger.
My Mom wanted to buy my old Systemax and was willing to pay $450 for it so I bought what I could to stay in that range. I ended up building the first system for nothing. :-) I liked the motherboard so much that I put the same thing in the second system for my granddaughter. I had parts from an older computer and didn't have to buy CD drives or anything so I came out pretty good on it too.