What PSU would be needed for a mid-range computer?

Question

I am building a mid-range computer primarily for gaming and graphic design. With the following components, what power supply unit would be good, in terms of having ample power for future expansion, with good efficiency and quiet operation, but most important, reliability in the long (5+ years) run?

• Gigabyt GA-H67MA-UD2H LGA 1155
• Intel Core i5 2300 2.8GHz
• Crucial CT2KIT51264BA1339 2x4GB Kit
• ASUS HD 6850 DirectCU
• Intel X25-V 40GB SSD
• 2xSeagate 7200.12 1TB HDD RAID 1
• Antec NSK-3480 µATX Case

Answer 1

You have asked "What PSU"..

If that means how much power your PC will need, this online PC Power Calculator can give you an idea.

If that means what brand you need, I cannot say.

Answer 2

Find out what your components require.

That being said, you generally can't go wrong with a 500W PSU.

But like I said, check what your components require and recommend.

Specific manufacturers... I like Corsair.