I game, like to have open 100 web browser while listening to music.
Basically...if i get the amd processor, will it do everything i expect the i7 to do?
Also, the performance increase of the 5850 over the 5770 should be pretty satisfying!
Is this a good trade off? getting a 5850 over a 57770 but dropping the cpu down?
Since your primary interest is gaming, I'd go with the AMD setup with the better video card since that is the limiting factor. However, if you live near a Microcenter, they have the i7 930 for under $200 and the older 920 for under $180. You didn't include any component prices so I dunno if you were aware of this.
^+1, go with the AMD for gaming. I recommend overclocking the CPU and of course getting a good CPU cooler to accomplish that. The AMD CPU will do everything you expect it to, so long as you don't do a huge amount of video encoding ^_^. Even then, there is the GPU accelerated encoding for ATI cards, but like the CUDA accelerated ones there are complaints of some image degradation.
For gaming between the 2 systems you have there the AMD w/ a 5850 will definitely perform better.
I would try an i5 + 5850 build and see if the cost is closer to the AMD.
I5 + 5850 > Phenom II + 5850 > i7 + 5770.
If the AMD system is still significantly cheaper then it'll still work plenty fine. You won't be able to tell a difference between these high end CPUs (i5 and Phenom II) in gaming until you throw in a 2nd 5850 or upgrade it so the i5 would be more for the future, as far as gaming performance goes anyways.
Not sure if you're factoring in the i7 920 at full price or not (~279) on newegg, but Microcenter has them on sale for 179$, and the i7 930 for 199$. If there is a location near you, I'd suggest picking that up. You'll be able to get both a better proc. than the current AMD build while still packing a 5850. You can only buy the procs at a microcenter store, but there's a store location finder on the right side
The reason why i originally chose the AMD for the cheaper system was so i could get the radeon 5850. He found a way for me to get both the processor and the graphics card i needed. Kudo's to mr azn. Thx buddy. I shall return the favor