I got the choice to either buy 2x 5970's and hope that the 5990 won't be out a week after my purchase.
or wait for the 5990 to get released, i am planning on watercooling whatever i buy of them.
The 5990 are not real graphics cards by ATi, just a marketing name given to an overclocked 5970 by sapphire. You should be fine just doing that overclock on your own seeing that you're planning on water cooling, so i say, pull the trigger on the 5970's
Right- the 5990 is really only a factory overclocked 5970. Buy the 5970s now, and you can overclock them yourself to the same levels that 5990 will be clocked at, especially if you are going to watercool it. Just get the 2 5970s and turn them into 2x5990 yourself