Want to build a PC for my kids (and one for dad, I mean MOM)

Hello, I have been reading this site for a week now and there are lots of questions as to what components would make a great system. Most look as though they are geared towards gaming and video editing. I on the other hand need recommendations on components, either Intel or AMD, that are considered middle of the road. Would rather buy a video and soud card rather than rely on the features on the mobo since what I have read so far about onboard video/sound has been mostly negative. I have two sons ages 13 and 14 and I would like to build them each a computer for this upcoming christmas. I would also like to get rid of my current pc (AMD 1800+) and build a nice one for me (and the wife). I would like it if you seasoned vets out there could list mid-range compents from the case to the keyboard. Obviously price is a factor, I have all year to track prices and snatch up a good buy here and there. My sons use our computer a little and my 14 year old is really into his MP3s and stuff. Gaming isnt that big of a deal since they have an XBOX, XBOX 360 and a Game Cube. Although I will keep my eyes open for a good deal on a video card. From what I have read I guess I am looking for an Intel 775 C2D mobo and CPU or a AM2-3800 mobo and cpu set up? I would like to have a list ready know so that I can have something to go buy instead of bouncing back and forth and wondering everything will work good to gether. Thanks in advance for your inputs.