Elbow Beards, GTA V single player is a hell of a ride, even if the story is trash. Multiplayer is mindless fun, and a money pit, don't get sucked in too far. There are much better online games.
Anyway, do yourself a favour and check out Witcher 3. It's not the type of game I usually have any time for, but I have 200+ hours. It's incredible. The graphics are stunning, the story Is stunning, the amount and variety of gameplay is mind-boggling. It's the best thing I've seen since Half-Life 2 or Mario 64, makes Fallout 4 look like a joke. Plus, it's on sale now, you can get it for £20. Even if you go for GTA now, I'd say get W3 while it's still cheap. Every PC owner should play it.
£619, and as for gaming, 20% faster than a Titan X, usually slower than 980s in SLI.
Bit of a rip off card for the early adopters. Price will drop when non-reference cards come out, but even then, I expect another drop within 6 months. 980ti's overclock really nicely, and the 1080 probably doesn't. Upshot is that you can already get factory overclocked 980tis card that are within %15 of a 1080.
1070 will be within 10% of a 980ti for around 350. Realistically you won't get a decent one until July.
AMD Polaris is coming around that time, should give us 980is performance for ~250. Their high-end cards might be coming in October, along with Nvidia's 1080ti (that will be worth looking at for sure)..
The big push with all the new high end cards was supposed to come from HBM (high-bandwidth memory), but it's proving very difficult to manufacture in volume, so we're getting an 'overclocked' version of the memory we already see in the 980ti,970, 390, 290. So anyone with a 980ti can be pretty happy. I've got a 970 and I just can't find a reason to upgrade ATM.