Having not tried a 7D yet, if it were up to me I'd seriously consider a 7D over a 1D3 at the moment. The one REALLY outstanding feature the 1D3 has over the 7D is dual card slots... which unfortunately, is VERY important to me. For many of the other features, the 7D as leveled the playing field or made up a lot of ground.
The attractive part about the 7D over the 1D3 though is your options for wide to normal range lenses. There are a plethora of ultrawide lenses you can choose from for 1.6 crop. For the 1D3, there really is only the Sigma 12-24 and the 14mm primes, unless you don't mind modding or using 1.6 glass. As for normal range zooms, the 24-70 and 24-105 are just not wide enough to me for normal range zooms, while you have many many choices for 1.6 for a good normal range zoom starting around the FOV of 28mm. It's a bit frustrating in that area on 1.3 crop. That's just my take on it.
But if you are shooting mostly telephoto stuff then it's awesome. I'd take the 1D3.