Agreed. Anymore would be a waste of cash. 1GB is almost too much for what you'll be needing it for, however, they will be the odd occation when you will. And 2GB's will be future proofing for you too. Dual channels a must for a good CPU such as that.
Get some 500MHz stuff, you'll need it for the 1GHz HyperTransport Bus. Or even better, get some 550 - 600, and overclock by increasing the FSB instead of the Multiplier.