Right now i have 1 exhaust fan and 1 ps fan. I have the stock heatsink and fan for my xp 2400+. Which would be better to get to get a greater drop in temperature? 1 or 2 intake fans or a new hs and fan?

the HSF would give you the best improvement in temp.

i and others recommend the thermalright SK7. it takes an 80mm fan which gives good air flow at quiet levels compared to most 60mm fans...

whats a good 80 mm fan that wont cost me too much? What do people use?

sunon makes good fans that aren't too costly.
remember to stick to quality fans... you don't want your CPU fan dying while your not looking...

is it crucial that i try to cool my comp? Right now my temps are 40 idle and about 50 while under heavy work. Should i just buy the sk7, keep my stock fan, and buy a good fan once i get the cash?

I have an SK7 with a Thermaltake Smart Case Fan II on it. It can push like 75 cfm and be pretty loud, but it is also manually adjustable so you can balance noise & temps. The fans goes for about 10-15 bucks, depending on where you buy it.

If you don't necessarily need that much cooling power, I'd recommend a Panaflo 80mm. They're one of the quietest fans out there (and best quality), and come in different speeds (L1A=slow, M1A=medium, H1A=fast). Any of the three speeds can be had for $6.

Another thing to consider is that the air your heatsink pushes onto the CPU can only be as cool as the air coming into your case, so you might want to consider installing some intake fans.

it doesn't seem absolutly necessary that you buy a new cooler 50c for a high temp isn't dangerous..
AMD states that instabilty can occus at 60c.

that's a good idea, assuming that you have a fan that fits on your current cooler, get the sk7 and wait on the fan.