Hmm...64 players...you're looking for something 4x more powerful then the current config then...Do you have a T3 coming in to your place? Because you won't be able to support 64 Internet players on a cable modem, T1, or most DSL. Oh well, you didn't ask about that. I would recommend going with a dual amd opteron (251's) over an amd x2 chip...only because of the memory...hmm...If money isn't an issue, i'd get the latest opteron setup, tyan 4 way board with 8 gb on some flavor of linux. =D I mean wth right?! However...if money is an issue...but you have enough to upgrade a bit:
4800 X2 - $1000; 4600 X2 $800; 4400 x2 $700; 4200 x2 $550
2gb of ram - $250 edit: definately go with 2x1024mb like theRod said, over the 4x512 alternatives
windows xp - 32 - $250 (i would check in to what OS's other people are using though...linux...win serv...)
nforce 4 ultra chipset -$120
reuse: everything else unless you want to go with pure performance HD's...buy a couple of 2x72gb raptors in raid 0...or, 4 or 5 of the new SATA IO (called II on the nforce boards...)in raid 5 (but that will eat away at your available cpu...depending on how many programs you're serving this could eventually become a problem as the onboard LAN and Raid use a lot of cpu at heavy loads).
Alternately you could get a high end p4 ... the ah 840EE...it does pretty well when you have a lot of things going on at the same time, but typically doesn't do as well as the amd chips.
edit: In all seriousness though...i'd go out and check out what servers are out there right now on BF2. Ask the admin's, typically they rent from places, and you can get that info from them, or right off of BF2's website (or at least links to these places), and the renters' can tell you exactly what they use in their servers. Having a dual setup may not help you at all if EA hasn't set up their BF2 servers to work multithreaded...short of the overhead work (ethernet, raid, sound, etc...), or in the cases where you're serving more then one program.
F@H:
AMD: [64 3000+][2500+][2400+][2000+][1.3][366]
Intel: [X 3.0x3][P4 3.0x2][P4 2.4x5 down][P4 1.4]
"...and i'm not gay" RX8 -Greatest Quote of ALL Time<P ID="edit"><FONT SIZE=-1><EM>Edited by apesoccer on 07/06/05 04:21 PM.</EM></FONT></P>