I'm one of those guys who has been wanting to upgrade to full frame from a 550d but decided to wait for the 5d mk III...
Given the fact that you have waited for that long, DO NOT BUY THE MKII until a mkiii is announced. Just wait a couple of months. You have a great camera and a great lens, there is no need to hurry.
I would say I agree if you don't really really really want a full frame. But if you do - buy it. It's a sweet camera. It's a lot of people's favorite camera.
Every time I look on Flickr I instantly can tell if a picture was taken with a 5D - they have an amazing look to them that I haven't really seen other cameras produce.
I still say buy the #$%*ing thing. Sell it when/if the iii comes out. You will still get a good price for it.