This is my first build and i wanna get some oppinions on it http://pcpartpicker.com/p/wNJK
Would it be worth upgrading to a 7850 gpu?
Yes, the difference will be great. Also, I'm not too sure that 880 chipset mobo will support Vishera. The least I'd get it with is a 970. Like the MSI 970A-G46. Then, that HDD only has 32MB of cache. This has twice that. It might give you better access/ read times. It's only a few dollars more, so you have nothing to lose. Get a 7850, or if you can fit it, a 7870.
You know what, just look at this. The jump from a 7770 to a 7870 is phenomenal. If you can spend the extra before the rebates and discounts, it's well worth it.
http://pcpartpicker.com/p/yges .
Maybe a cheaper case and an aftermarket cpu cooler.
change it to an NZXT GAMMA case and get a fx6300
http://pcpartpicker.com/p/yh9W