That is a build I did real quick. You can shave off a bit more money, by getting a cheaper PSU, and possible 2 x 1gb of ram. But in general your build from what I could see was pretty spot on for your price range. Obviously second hand would increase the price/performance, but for someone newly assembling that could be an issue with knowing what is your fault, or if you got jipped by someone.

I put the ram at 1.5 v instead of 1.65 v, and the a pretty good quality PSU as they can lead to problems when building. I recommend getting the 3240 instead of 3220 I3, because it's the same price and every 100 mhz helps being more compatible with more games.

I also hesitate to recommend this build as you might not be happy with your results. A lot of the Screen shots and videos you might see probably have 4.0 GHZ+ processors, and better videocards. But, I can't be sure, and I would get other peoples opinions that emulate. I forgot their usernames unfortunately. Maybe, Soleron. Pemalites above advice is good, and he in general gives good advice.

It won't destroy your CPU if you use adequate cooling. The stock cooler should be enough to do a nice overclock on it, so don't worry too much, just keep an eye on the temperatures, if it gets too hot, lower your CPU clock till it reaches an acceptable level. Since your CPU isn't unlocked, you won't be able to overclock it well, so get the highest clocked i3 you can. Since the only way to overclock a locked processor is by upping the base clock of the entire system, maybe you can get another 100Mhz out of it, but that's it.

Probably want an i5 for Dolphin emulation. Graphics card is fine for medium settings in modern games and should handle emulation well too.

Thank you all for the advice and stuff! overall I decided to get a Slightly better processor, and settled with a Intel Core i3-3240 @ 3.4GHz, mainly because it had more GHz but for the same price, and from what I heard the more GHz the better dolphin runs. I just hope it will be enough, but from what I heard from you guys im pretty sure it will :)

thanks!

you might consider an amd fx-6300 but I'm not sure if it is better for dolphin.

Nah.
Dolphin is heavy on 2 threads and Intel dominates AMD in anything that's lightly threaded.
You would need to hit roughly 4.5-5ghz to make the AMD chip even worth a consideration and chances are it would still be slower than the i3 at stock.

This is one of the few cases where I would actually recommend Intels slowest over AMD's fastest.