Sounding better and better.
Those temps aren't too bad for a stock cooler. If you are planning on going much higher, a better cooler or better airflow in the case will help tremendously.
I wouldn't recommend 3 sticks if overclocking. It might work, but will more likely be flakey.
Based on feedback here and what I've read I would go with G Skill, Mushkin, or I've heard A-Data is good ram also.
Here's some just to browse..
For what it's worth, if you're staying on XP and just mostly game, email surf etc...2Gb is really fine. If moving to Vista 4 will show a difference.