Meh to all three. Nvidia has finally made themselves relevant again with their kepler rebranding and price cuts. AMD needs to deliver something fairly soon. Before the 650 boost, 760 and 770, there literally was no reason to buy a green card between $150 and 300$ and only a 670 if you somehow managed to miss one of the zillion 7970 sales everywhere at the time.
Now, the 680(770) is where it always should have been, displacing both the 670 and 7970. The 660ti has been put out to pasture, along with 7870xt and 7950 for the most part. Watching carefully will still net you a 7870 Ghz for about $10 more than a 660, so that one is still worth it, but that's *ALL* AMD has going for it. It's hardware can't carry the day anymore.
If you already have a couple of the games in the AMD bundle, the hardware and price can't make a compelling enough argument to buy red.