It's largely personal preference, but I've found the ACX and Windforce to offer the best cooling and acoustics. The Twin Frozr and Direct CU in particular are close behind though.Thanks but why not the MSI Twin Frozr or the ASUS CU series?
Also, I have not upgraded my graphics card in ages. Is it just plug and play or do I need to uninstall the drivers of my 560Ti (latest drivers installed) before removing it and putting in the new 760?
It's probably wise to remove all GPU drivers when you switch cards.
Definitely look at overclocking your 2500k, if you're worried about extra heat a new heatsink like the Coolermaster Hyper 212 EVO/Plus should keep it in check nicely.