I dont do any over clocking because I really wouldnt know where to begin. I havent over clocked anything since my old P166, and that just involved changing jumpers on the board to make it run as a P200. 8Gb ram sure I could upgrade that since it's so cheap It would only cost like an extra $30 give or take.
HD well 1TB would be nice, I would end up just wasting all that extra space, I dont have a hole lot of software right now. Sold my old system a few years ago cause I needed the money.
Define gaming, I don't do any of the hardcore gaming like BF3 and other FPS games, I play MMORPG's, not into Skyrim either. I have looked at the 7850 but until there's a price drop I can stick with the lower end Radeon 7 series or higher end 6 series. I have not been a fan of nVidia since my crappy 8600gt.
Cases I looked at both of them and they don't fit my tastes, the Antec is too plain Jane, and the HAF912 while nice doesn't fit my idea of sleek. I actually like the looks of the Thermaltake V9 VM400M series, something along those lines would look nice to me. I like the HD cages to be turned 90degrees for easy install/removal of the drives. I'm open to other suggestions for a sleek looking case.
PSU I do plan on crossfire later so I'll need something with a bit more juice than a 430 or 500w, which is the reason behind the 650W choice. Modular is prefered but not required. Always better to have more power than you actually need, this gives you some wiggle room later. the 7750 requires a 500W for crossfire and th 7770 requires a 600W, which is what the 78xx series also requires.
Mouse and keyboard...well I dont have either and I like the looks of them. I could have picked the $160 keyboard logitech offered. I just wanted lighted keys and something that was geared towards gaming, standard keyboards work but it's nice to have the extra keys to bind stuff to.
Monitor I dont need I plan on hooking up to my 32" HDTV through HDMI, 1920 x 1080p is good enough resolution for me, hence the reasoning behind going crossfire later, some cards struggle with max visuals at that resolution. And yes I know the 6750 will definitely struggle here.
Motherboard has features I want, Z77 will allow me to upgrade to ivy bridge if I choose to go that route, which I currently see no need to do. It may be pricey but it does crossfire which the next cheapest from Gigabyte does not (I could have read the specs wrong on the other board).