I already am pretty set in stone on the components, i5 2500k, GTX 560Ti, 8g of Ripjaws, 750w PSU, ASRock Extreme3 Gen3 Z68, 212+ Heatsink.
My main question would be, what kind of cases would be recommended? I'm spending most of my budget on the parts, looking to spend <$100 on the case, but don't want something that will look too plain, but I also want something that will have enough real estate fan wise.
As a small, less important question, with those parts in mind, how much wattage in a PSU would be needed to be safe in case of overclock and expansion of RAM.
You would be fine with a 500W PSU. The GPU uses around 285W at full load, the CPU around 150 (not that they'll ever be under full load at the same time), and the mobo, HDD etc maybe 50W, though probably much less. The RAM is absolutely negligible.
You should choose your case on almost purely stylistic grounds. Check here to make sure there's not something terribly wrong with your choice, but most cases these days perform perfectly well. I'd go at least $50 for durability, but again, check if a cheaper one looks nice. A few popular ones are the NZXT Phantom, the Cooler Master Storm Scout, the Rosewill Challenger and the Antec 300. Trawl around Newegg in the ATX section and see what catches your eye.
Any ATX mid-tower case is sufficient as far as real estate. Also a 750W PSU is more than enough for overclocking, extra ram or a second GPU. You could even get away with a high quality 600W-650W for that system and still accommodate upgrades and have more money to put towards a case or just back into your pocket. If you would like some suggestions on good PSUs in the 600W range let me know.
As for the question at hand some nice cases can be had for under $100. I personally like Antec, ones such as:
I appreciate all of your advice, everyone. I am looking into each of the cases you have linked. In the time between posting and checking back now, I found this model I was particularly fond of. The green LED really suits my interior design. Any thoughts on its functionality? http://www.xoxide.com/apevia-xtcase-green.html
My roommate had a PC in an Apevia case and it was on the flimsy side and that also made it very noisy. That site doesn't say how thick the steel it's made out of is, I prefer at least 0.7-0.8mm thick with 1mm+ thick being optimal. My Antec Solo is sturdy enough with it's 1MM SECC frame I would feel comfortable using it as a seat.
My intention is not to scare you away from that case if you like the look of it, maybe just try to find out what it's made from, I cannot find it on apevia's website either. The flimsier they are the more easily they will dent and the noisier they will be.