I tend to favor Corsair and Antec for my PSUs
I know I haven't given you a specific one to look at, but here is my ten cents:
"The PSU is one of the ONLY units for your computer that doesn't really change in design (so in general, it has a super long lifespan). So invest your money in something that will last."
Ex: you may not use it now, but if you get an 850w PSU, it gives you the option in your future to scale up to a good SLi/Crossfire config. So this 850w will last from build to build.
Last Ex: You can save money in the long run!(prices are by no means exact, just using them for example) You buy a 500w PSU now for $50 and pass up the 850w for $100. Well, down the road you get the chance to buy a GTX580! Well, then you want to go SLi so you can do Surround! Well, now you have to go back and buy the 850w for $100. Now you have spent a total of $150 when you could have just spend $100 in the first place.
So...in general, I suggest looking into the direction you may want future builds to go and plan for that!
I hope this helps you in some way