Some help for upgrading to a faster drive/drives

Hey guys,been looking around into upgrading to a faster drive,my current setup is:
ASUS Crosshair 3
AMD 1090T @4.0ghz
2x ATI 6870
8GB Corsair 1333Mhz 7-7-7-20
WD 500GB Caviar Black
Corsair 1000W

I mainly use the PC for gaming,my HD is barelly iven used cause I dont store who knows what on it,tons of more memory to be used....

as you see from the whole setup this is a pretty descent speed wise rig,all my hardware scores on win7 experience between 7.6-7.9 except for the HD that scores arounf 5 ish.

I really dont care about the win7 experience but more like my own experience in gaming.This is my first build and I never ran with dual or trio drives in it,was only the 500GB caviar black.So here is my thinking after I spoke with buddy of mein about upgrading to an SSD.He said if i buy 64gb SSD will overall increase performance of the PC,yes maeby will increase windows booting,uploading running some win aplications which is irrelevant to me,but spending money on something that after installing win7 I will barelly have 10gb free space left on it to install a game is not a good deal....  

So was looking for some SSD's and Velociraptor

I found the Crucial M4 128GB for around $177 and Velociraptor 600GB at $220

Should I go with both,or just the SSD would be fine since I can see my self only keeping there my main MP games such as the upcoming BF3 and Red Orchestra 2?

This is what I'm lokking into it:

-Crucial M4 128GB SSD for MP games (Red Orchestra 2 & BF3*for now*)
-Velociraptor 600 for whatever games
-500GB Caviar Black (IDK if I can iven sell it or maeby keep it for some music? but the 600GB Velociraptor is plenty....IDK)

Any opinions?