Yes, 47's spot on the money. It's definitely a nice upgrade - one you'll notice, for sure.
I recently bought an i5-3570K on black friday, so I'm going to build around that. It cost me 150, but reg. price (I think) is about 220.
so:
CPU - 250
Motherboard - 300
Power Supply - 200
Case - 120
Ram - 30
Video Card - 300
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1200, tax in. This is, of course, a very rough estimate, and it could be actually be much lower.
For me, I'll only be needing a motherboard, ram, and whenever finances allow, a better GPU.
I'm building another plexiglass case (I have a good case to use in the interim), and already own some good SSD's, optical drive, a good PSU and possibly even CPU Heatsink/fan combo (I'm not so sure it will fit Socket 1150, for i5. I doubt it
)
If I may ask, what do you plan to be using your computer for? Perhaps I can find some well-known parts combos and price some stuff out for you. As for building, it's fairly easy as everything only plugs in one-way - it's hard to fuck up. Do not pay for labour to build it - hell, I know you're close to me, I'll come build it for you. Oh, and I'll give you Win7 Ultimate 64-bit