if you want to play games in 4K you need a killer Gaming PC (SLI/Crossfire 780 or R9 290's).
Current gen games have issues with 1920x1080 and 60fps.
No, it doesn't look like thats going to happen this gen, a lot of game's aren't even doing full 1080p. Maby the ps4 will support 4k movies but not games and its not worth getting a new tv over.
Whatever TV you do buy you might want to check it here for input lag especially if you play FPS or Fighting games.
Personally I'm not as sure about 4k I think by the time everyones ready to crossover there will be a 10k or 25k I'm not so sure it's the next HD, it might be more like 720p when everyones gone 1080p