uhm... I hope this doesn't put too much of a damper on your day but the MB you currently have will not support a Phenom II x6, only Phenom II x4
4GB of RAM is definitely on the lower side of the scale, and you would notice a boost in performance if you added more, but it is not necessary. It is also pointless to add more RAM if you are running win 7 32-bit, as you would have to reinstall the 64bit version to even use the extra RAM.
You'll be pleased to hear that I upgraded to an Asus M4A87TD Evo with 8GB of DDR3 Gskill RAM. I just reformatted my whole drive. Windows 7 took about 20 minutes to completely install. I can already notice the difference of the processing power this Phenom II is making.
Thanks for bumming me out on that fateful day and subconsciously helping me choose to upgrade.