Your best bet is to wait. There's a lot of garbage floating around the internet now about 4K resolution, when in reality these resolutions are only being used to test X card vs. Y card. I'm a hair-spread from grabbing dual 780's but have to wait also. The VRAM on the 290X is a little bit better than the 780 (if it matters). The 780 Ti will likely have a version that has more than 3GB VRAM (We just have to wait and see).
Definitely wait for the aftermarket 290X coolers. I extremely doubt it will be anywhere near as cool as 700-series cards, but it should reduce temperatures somewhat. AMD says the cards can run at 95-Celsius all day (and they do, right out of the box), but that's too hot for some people.
Oh, and allegedly the 780 Ti will be released on the 7th of this month.