I'm using the Athlon 64 3700+, and having a great time with it. My rig is as follows:
CPU: Athlon 64 3700, socket 754
MB: DFI Lanparty NF3 250GB
Ram: 1gig PC3200
Vid: Geforce 6800GT, AGP 8
HD: 80Gig primary, 120gig secondary drive, both Ultra DMA5
Other non-speed related stuff:
Case: Antec SOHO big grey metallic windowed thing
PS: 470W Antec
CD: Plextor DVD+RW primary, 52x CD-rom secondary
Monitor: 19inch Sony LCD
It's a fast rig. I originally had a DFI Lanparty NF2 and an Athlon XP3200, and got the Geforce vid card for that. So it's an AGP board. When I was next upgrading, I didn't want to ditch the vid card, so I was stuck with AGP motherboards. I had a good experience with the DFI lp2 board, so I opted for another DFI board, this time NF3. I got it for $99. The CPU cost me $200+, can't remember right now. It's been a while.
Overall, the performance is great. I can't complain. I have room for another gig of ram, I can always put more storage in, in the shape of larger, faster hard drives (the DFI NF3 board gives you the option of Ultra ATA or SATA), so I'm sorted for the next while. The Geforce 6800GT wasn't on the market awfully long, but it's fast as hell. I'm glad I bought one when I did. I won't be hurting myself to remain with it. The next upgrade I make will have to be toward a PCI-E solution, and I can't afford to do that for a long time
