fileserver hardware reccommendations?

[Luigi]

I'm building a fileserver, for a group of 25 users. i run a redhat shop, so it'll definitely be RH8. I'd like to have all my users run their home folders off of the server, so speed is important.
that being said, all this is is an NFS fileserver. nothing else at all.

what hardware should i get?

here's what i have planned:
CPU - 2 x AMD ATHLON MP 1600+ FSB266
M/B - asus A7M266-D dual processor
- 2048mb DDRAM
- adaptec 2400a IDE RAID-5 card
- 4 x Western Digital WD1000JE (100gb/7200). 3 for active use, 1 for backup

any suggestions? does this sound like gross overkill to anyone else? i don't think i need anything near such a powerful system for a straightforward file server...but how slow can i go without the users noticing?

btw, it's a 100mbit network.

thanks!