I've built my last 4 computers, since I was a senior in high school (I'm now a 3rd year law student) - I like to keep my pc up to date.
First...Good case! I have a Coolermaster ATCS201 Aluminum case (4 case fans) So far it has been great
Second...Mobo and Processor...if you want the best go with the P4EE 3.2 and an Asus P4C800 deluxe mobo, IMO it is the best.
Third...RAM...I recommend at least 2 sticks of 512MB PC3200 (3500 is a waste because the fastest bus speed out now is 800Mhz and the pc3200 in dual mode give you exactly that so you dont waste ram speed or cpu cycles = super efficient) Either Kingston or Corsair are the best, opinions vary, I use Kingston Hyper-X.
Fourth...HDD...I love Maxtor...go with two 250GB Maxblast 9 SATA drives in RAID mode! Sweet, I wish I had that
They have 7200RPM and 150SATA (not native but still the fastest out there for the drive space)
Fifth...Video Card... I like Nvidia so I would wait and go with the NV40 that should be out in April or March...so pick up a cheap card to last you until then...Geforce 4ti 4800 or the like, keep it cheap or wait because the NV40 is gonna rock (and it will be $500 bucks)
Sixth...Sound Card... I love the Audigy 2 I have from Creative...LOVE IT...BUY IT
Seventh...Speakers... I have some Klipsch Ultra 5.1... they rock, nice dual 8.5" sub and sweet satilites, really recommend them.
And that should do it...it wont be cheap but it will be the best on the block...I'd say a good 3 grand at least