It's something that's hard to explain to people, wanting to build a non-bleeding-edge PC for gaming. I'm pretty much a console purist, with no experience when it comes to PC tinkering or graphics card selection. It seems like the process might be simpler with the creedo "get the newest bits you can afford" but it gets complex fast when wading through years of dated hardware looking for a bargain. So here's what I'm looking for:
I want to build a tv console type pc box (htpc?) that will run a handful of steam indie titles, and some windows homebrew stuff. The most demanding software I'd want to run would be starcraft 2. I would like to use gamepads with it (snes usb controllers!) and pairing bluetooth controllers would be useful, so I guess I would need a bluetooth card? I have a friend getting rid of their old computer parts, so most of the box is put together, tho all I can say off the top of my head is it's got an i5 processor. I need a graphics card and a power source.

What I'm not looking for: I don't want an Ouya or Steam box. Neither are flexible enough to run the homebrew windows games of yore, I'm thinking Super Mario Wars. I don't want a streaming box, I've got enough consoles doing that already. I don't want a future-proof machine, I don't see a lot of high-end pc games in my future.

So questions:

What kind of graphics card should I be looking at? I'd like to keep it cheap, but I feel like i can find something that's dated but could still run the gamut of new-retro style indie stuff i wanna play on my tv, AND my one PC game crush, SC2.

Is there any benefit to an HTPC case besides being able to fit in a media center? How hard is it to work with one of those?

Are there any app-launchers for windows that will work with a game controller?

Thanks for the help!

Have you considered foregoing a discrete graphics card entirely and just using Intel's integrated graphics? If you look for a CPU with Intel HD 5000 integrated graphics, I think that may serve your needs just fine. Not to mention it'd be a quieter machine that draws less power. Though I think only the latest Core i7 CPUs will have that. It's an option.

Edit: It seems that the 5000 series HD graphics is reserved for the mobile variants of Intel's CPUs. 4600 seems to be as good as it gets when it comes to the desktop CPUs.

Ah I hadn't considered that, thanks for the idea!