Memory was another tough call. And I went back and forth on this several times. My selected mother board supports DDR2 PC5300 memory but there are a lot of options, and memory can be the detmermining factor in the ability to overlock a pc.
The final conteders were to buy a high end gamer specific memory say a CORSAIR Ballistix ($159 for 1 GB at Newegg) or to buy 2 GBs of good ram from a second tier supplier. I changed my mind on this several times. CORSAIR Ballistix is a safe bet for overclocking, it gets good press all over the forums. But for some of the current games, 1 GB can be a bit tight. Going to 2 GB of Corsair is possible, but that I would really rather pocket the difference in the anticipation of a near term desire for a monitor upgrade.
I was still undecided on the day I was going to place the order at Newegg. The final choices were the 1 GB of CORSAIR for $159, or 2 GB of Patriot memory (great specs, but not very widely covered). At the last second, I tripped across a forum entry on Newegg where someone had bought the exact same motherboard, and the exact same Patriot memory and overclocked the system from 2.67 to 3.6 without any voltage increases and with complete stability.
OK, the stars are aligning, I'll throw the dice and go with the patriot memory.
Final Price: 2 GB Patriot PC 5300 timing 4-4-4-12... (Newegg price 178.99 with a $35 rebate)