The i5 2500K is commonly accepted as the best gaming CPU, and it's also the cheapest of the bunch.
The only reason to opt for the i7 CPU's is if you do a good amount of video encoding which is one of the few places where hyperthreading becomes worthwhile. The 2700K is more than likely just a binned 2600K and isn't really worth the extra money over the 2600K.
"Movies" do you mean watching movies or encoding movies. Programs like Handbrake can take advantage of HT so buying a Core i7 can come in handy since on average it will probably reduce your encoding time by around 18%.
I am using a i5 2500K CPU. My advice is go for i7 2600K, you said its mainly for gaming and photoshop and watching movies for now. But how about in the future, you might want to to do some video encoding, rendering, and conversion from one format to another. I7 2600K is right for you. For future proofing, i7 2600K is the right choice. For gaming and hyperthreading its the best CPU choice for you.