How about an Asus K8S-MX with a retail A64 2800+? The CPU/mobo combo price is quite close, it's more powerful, has hardware-enforced Data Execution Prevention, 64-bit ready, and the mobo's passively cooled. It has one memory controller, so dual-channel's a non-concern too. I would probably use one Corsair ValueSelect 512MB PC3200 module, or else Crucial if I were in a paranoid mood
That mobo does have only one IDE channel, so you'd probably want to use a SATA hard drive here.