I am upgrading my computer and I need to choose a cpu, I can go for a E6850 core 2 duo 3.0GHz or core 2 quad Q6600 2.40GHz

I am not a hardcore gamer. I play counter strike from time to time with some gta san andreas... I do video encoding once a month and I code in c++. Also I am running 2 virtual machines... (linux os's) what is the better deal, and should I get good ram or use old junk..

I am new to harware overclocking and probably wont get experienced soon.

what is best for photoshop and adobe products?

which one will go faster in the end, is 2 x 3.0 faster than 4 x 2.4???

The choice of CPU is often dependent on the motherboard especially when considering Quad cores. Only motherboards released within the last year are really setup to utilize Quads.

What is the make and model of the motherboard?

As to the Adobe questions you might want to post a different thread in the software section for a better reply.