both the ivy and haswell chips have overclocking headroom, its just heat becomes an issue with simple coolers like a hyper 212. sandy bridge is the best as far as thermals, that said going with the newest tech is better as haswell @ 4.4ghz is as fast or slightly faster than ivy @ 4.6ghz. if you have a 240 rad and nice d5 style pump on haswell, ivy, sandy…. thermals are not an issue anymore and 5.0ghz is almost a guarantee on all the chips with decent voltages.
if your just an average home hobbyist doing photoshop, a 4770k is more than enough because shaving down 20sec render to 15sec render by going to a 4930k isn't a deal breaker.
the 780 is very superior to the 770 and over clocks very well.