So, I've finally got some money saved up for a new PC, and I thought I'd seek advice. I plan on building it myself, to save money, to learn more about PCs and know my machine inside & out, so I can set it up to be upgradeable, and just because it seems like (slightly scary) fun!

It's going to be meant for gaming, and I've got about $800 (though if I can spend less without too much loss of capability, that's cool, too). I'm just going to use my old 19" 1440x900 monitor for now, I'll get a new one at a later date, so that's money saved right there.

I want something that'll play today's games at respectable settings, with room to improve down the road.

Here's what I'm thinking atm:

Processor: i5 2500k (overclocking is something I'm curious about, too)

mobo: ASUS P8P67 Pro

power supply: I was thinking 750w, but maybe 650 is enough? Regardless, there's an astonishing difference in price for PSUs even of the same wattage from the same manufacturer so idk.

GPU: GTX 560ti. Just a matter of picking which one. How much of a difference does 2GB memory make compared to 1GB? There's only like a $20 difference. Anyone have a specific card recommendation?

RAM: 8GB. This stuff seems cheap enough, though I'm not sure how much difference there is between 1600 and 1333

Hard Drive: I'll find something. I figure 500GB is fine for the moment. These seem more expensive than the last time I checked, though...

Optical drive: I'll likely just pull my old one out of my crap PC. It ought to work, right?

Case: Here I'm lost. I know i need an ATX, but beyond that... I want something inexpensive, but that has room for expansion. Never having built a comp before, I feel like this is one choice I could really screw up on my own.

Tell me if I'm missing anything. Hmm, with just a quick eyeball guesstimate, I appear to be over budget. How'd that happen? I was sure the last time I mucked about on Newegg I came in below that. :/