Should I spend $100?

Ok, I have $100 to make a change...do I go up to 1Gb dual channel PC3200 or replace my PSU?? Neither of my existing components are showing signs of problems but they are the "most generic" items in my rig. My current 1Gb PC2700 is running dual channel even though they aren't matched sticks (maybe Dell checked on it first??).
The 420W PSU came with the Raidmax case and together was only $50. I am assuming you don't get something for nothing so the PSU is likely substandard (I haven't yanked it out to check the ratings yet) but so far I am running steady at the OC stats I have posted.

Or do I save my $100 for something else? I know if I save up for a new CPU then my existing RAM will become an issue, and the PSU will too. Ah, the vicious circle of upgrading. BTW...$100 isn't a serious purchase for me, the RAM just made itself available and so now I am in a buying frenzy again.

(I am starting to think the PSU might be the way...one time investment)