rtcvb32: I'd hesitate to overclock. You may get more performance but burning your chip and heavily reducing it's life seems like it's not worth it (to me).

I suppose, do you really NEED more speed? If just having more cores would be better, then go for that, namely the quad or hex core (4-6); Although a lot of programs don't support multiple cores, there are programs for those who know what they're doing to still effectively use most of the processing power. And a number of programs/games/emulators/engines DO use multiple cores when offered a chance.

Personally i've taken to putting my computer's in low power (power saving) which is about 50% processing power. This seems fine for 95% of the tasks i work on, and every so often i have to boost it to balanced.

ET3D: My experience with overclocking is that once I feel the need for it the result won't satisfy me anyway, and I'd end up upgrading.

Strijkbout: I was amazed how much more performance I could squeeze out of an obsolete system.

HG1995: Just two more questions. I've got a 4gb crucial kit 240 pin 667 that's been waiting for me to install win 7pr 64bit.
Will this work with the 4gb corsair RAM installed? Exact same specs. I couldn't get the 667 corsair version only 800 available, so go the crucial kit.

HG1995: Also Motherboard has the 4 slot 2 channel setup should i have the 2 corsair sticks in channel 1 and crucial in 2?

Strijkbout: It should work, unless this is a rare case where the sticks are incompatible.
Strijkbout: Install them dual channel according to your mobo's instruction manual, in most cases this means slot 1-3 or 2-4.
I had to install my sticks in 2-4 to leave space for the CPU cooler.

OlivawR: Then and Now: Almost 10 Years of Intel CPUs Compared

For 150$/€ I think you could find a I5 2400 and LGA1155 motherboard (second hand).