What sort of PSU should I be looking for here?

In the process of my first build here, but I'm stuck on a power supply for my first build. I don't want to spend money on a high wattage PSU I won't fully utilize, but at the same time I definitely don't want to buy a cheap one that will fry.
My specs are:
- AMD Phenom II X4 955 3.2 ghz Black edition.
- HD 6850 (Would brand play a significant role in Power consumption for the PSU?)
- Gigabyte GA-890GPA-UD3H
- Corsair 2x2 4gb DDR3 memory 1333mhz
- Western Digital 500GB HDD
- Coolermaster Gladiator 600 Chasis
- Samsung DVD writer.