This will be fun. I'll give ballpark prices off the top of my head as I remember them from newegg.com.
Aluminum cases are cool if he's into LAN parties, but it'll cost you over $200 depending on which one you get and probably blow the budget. It's hard to beat the Chieftec mid-tower with 450 watt power supply for about $70 if budget is a concern. By the time you add another case fan or two and a floppy drive, you're getting close to $100.
Now stuff this case with an Abit IC7 and 2.4C/800 CPU which together should be about $400 or so. An easy and stable overclocking goal would be 3.2 gig (12X267). The reason I suggest this speed is that it's a no brainer overclock without having to spend a lot of time and fuss with cooling (probably can get by with the stock CPU heatsink and fan if you use Arctic Silver thermal paste and have good case ventilation).
Plus... at 267 FSB you can use the 5:4 memory ratio which will give you DDR427. Therefore any good high quality PC3500 RAM can be used with aggressive timing settings for maximum performance. Corsair XMS, Kingston HyperX, OCZ EL, Mushkin black label, and TwinMOS are all worthy brands to consider. You'll need two sticks to run dual channel DDR in the IC7 mobo, so if you want 1 gig of RAM, then two sticks of 512 meg Kingston HyperX PC3500 will be about $250.
A good DVD drive and CD burner combined will be about $100. You should be able to get a good 80 gig ATA133 harddrive for under $100.
The IC7 has pretty good on-board sound, but you'll still need a good speaker system (at least 4 speakers and powered sub). If your friend is an audio nut, then he might wanna get a good sound card. Need either a modem or ethernet card, plus good optical mouse and decent keyboard. All this could easily run from $150 to $250 depending on what stuff you get.
Now we're down to the vid card and monitor. For a harddore gamer, it's hard to beat the Radeon 9700 Pro which runs about $300 and a decent 17" monitor will probably be close to another $150 to $200.
I added all this up and it's running about $1450 to $1700 depending on what options your buddy chooses. Not bad for an awesome gamer rig. With a little bit of bargain shopping and if you can scrounge up used floppy drive, keyboard, etc. and then maybe skimp a little of the sound system, then that should easily put you squarely into the $1300 to $1500 budget range. Another way to help the budget is to drop down from 1 gig of RAM to 512 meg, which should save another $100 to $125.
