Originally Posted by
Strakeln
My 2cp:
I'm more of a "more power, faster, now!" kind of guy, so take what I say with that in mind:
Processor: I'd prefer fewer, more powerful cores. Quad cores are more or less dual cores glued together and scaled down (speed-wise) to reduce heat. Currently, very few (possibly no) games use up to four cores - it's 1 or 2, max. From an end-user perspective, you will notice that a comparably-priced dual core processor will be faster than a quad core, as you'll have a faster clockspeed. What you lose is what you're not using, what you gain is faster performance. Not sure how easy it is to find dual cores nowadays, they were supposedly being phased out a year or so ago (which sucks, dual cores had significant design advantages that were lost with the move to quad cores).
Memory: more is better. Double it. I personally have not found the top-of-the-line memory such as Corsair Dominator to be worthwhile. Note that you need to have a 64-bit OS to use more than 3.5 GB of memory. Note that you also need the slots for it. I don't know mobos all that well but I'd be surprised to see yours have only two slots (so 4x2GB should work, someone will correct me if I'm wrong here).
OS: Get a 64-bit OS. Same price, will enable you to have 8GB of memory.
Video Card: I've fallen in love with the NVIDIA 2XX line. The GTS 250 sounds perfect for your needs.