You'll notice a tremendous difference in performace (as long as your video card isn't a bottleneck) if your motherboard can handle it. Sounds like you have been looking at pricewatch for your stuff; good on you!
If you have a card similar to GF2MX, it won't make a huge difference in gaming for you.
memory prices go up and down. it's a matter of the limited fabrication plants, current demand, and predicting future demand. so they seem to go up and down randomly.
if your board, power supply, and heatsink can handle it, i'd go with the 2400+. if your board supports up to a 266fsb then it's about the fastest chip you'll be able to stuff in it (not counting the rare 266fsb 2600+). the 2400+ is effectively 3x faster than your current processor which is quite a jump. then when you save up some more money you can upgrade your video card.
what board do you have? how many watts is your power supply? what kind of heatsink?
its a elite group (ecs) k7s6a or soemthing. i know with my BIOS it can support up to 2600+ 266fsb which iwas actualy thinkin about geting but im leaning with the 2400 now. I don't know how many watts my cpu is but if you meant my power supply it is 300W....and I don't know my heatsink....
If you're a gamer... you'd be looking at RAMs made by corsair; kingston or OCZ as they sell performance RAM targetted at those who want more juice out of their systems for gaming.
Will cost you an arm and a leg... just a word of warning.
ok well ihave a 300W psu but im thinking of geting a 400W one thats only 20 bucks! yup and its AMD aproved on teh site. wahoo! oh and where do i buy heatsinks and what kinds do i look for? im totally clueless on heatsinks