Hi kamran,
Corsair is a good brand, I am using a Corsair XH850W modular PSU and it comes with a five year waranty. A modular unit like this means you don't have lots of unused cables all over the place, you just use the cables required to run the devices in your computer. One other thing, if you have more than one hard disk in your comp. do not have them setup as an array. When set up as an array it can be slightly faster but if one disk crashes you loose everything.
Cheers,
Bill9