Your build looks good! I would, however, change the CPU to a Core i5 3570K. It's newer, a little bit faster has some new features and you have a great mobo for it. Also get the crucial RAM. It has better timings than the corsair and since they're priced equally that one is the better deal.
Thermal paste comes with the cooler.
At your budget I would suggest getting an SSD. The Crucial M4 128GB is an excellent choice.
Well i checked out the i5 3570K briefly and it doesnt seem like a win...ill look into it a bit more latter but i guess i wont get it
What made you decide that?
To answer your question about SSD you can read this article if you want a long answer.
The short answer is they are MUCH faster than HDD's and since HHD's are a bottleneck every time the CPU/GPU/RAM needs something from the HHD, you system wil feel much faster, smoother and loading/booting times are drastically shortened.
It seems to be very hard to find a good Sandy Bridge and Ivy Bridge comparison. So far Ivy seems to be overheating, i dont have a use for integrated GPU and the performance difference isnt that big. Tell me something more about it if you can some realworld differences taht i would find a use for in mainly gaming.