Ultimately, it really doesn't matter which CPU you pick. 3570k is faster at stock levels as it's based on newer tech, 2500k runs a bit cooler so can be overclocked higher. It's likely that with a moderate overclock there's very little between them. 3570k has some additional benefits from Ivy Bridge which might be beneficial, and so it's probably the recommended choice.
There's a bunch of good Z77 boards which come in well under your price cap. ASrock z77 extreme 4 is a safe bet. The Gigabyte GA-Z77X-D3H has a big chunk of money off it on Newegg right now, makes it much better value.
If you wanted to spend more, you could, but you'd need to see if there was anything actually worth getting on the really high end boards, other than elaborate heatsinks and colour schemes.
CPU cooler depends on how much you want to push your CPU. Nothing wrong with a 212 Hyper Evo for excellent value. If you want the best, the Noctua NH-D14 tends to get a lot of recommendations, as does the Phanteks version, but both are crazy expensive and the Noctua isn't much of a looker. There's a lot of other options but it really depends what you are aiming for.
As for changes, everything looks fine. You probably don't
need 16Gb of ram, and you don't
need a 750W PSU but you clearly have a healthy budget and it gives you options I guess. Additionally, it's perhaps worth pointing out that for your budget you can also buy a HD7970 which may offer better performance. There's not a lot in it though, especially if you prefer Nvidia, just worth a mention.
Also I don't like the case look