I'll weigh in as I've owned both bodies. The 5D2 will give you better ISO performance across the board. Great looking ISO3200 images with even modest noise reduction in post are much faster/easier to achieve with the 5D2 files than the 7D. Detail and resolution are also better with the 5D2 than the 7D obviously due to the larger sensor size (which also gives you more latitude in cropping in post).
The 7D is better at tracking moving subjects and capturing bursts of action - by far. The additional focal points are great for composition compared to the 5D2, though in real-world performance I didn't find them that much more accurate...YMMV. Also, the 7D seemed much more demanding from a lens quality standpoint than my 5D2.
It really takes no more time to process an ISO 3200 shot from a 7D over a 5D2, it is just different settings or steps in the action. After you build up these actions so you can replay them on any given image based on ISO results, it takes about the same time to run Action A over Action B, with the only difference in time in waiting for Action B to run something a bit more aggressively, or with a couple more filters. Yes, you start with cleaner results on the 5D2, there is no arguing that, but you can bridge part of that gap very quickly with good corrective actions you set up and run in batch on 7D images.
This image took less than 1 sec. longer to process on the 7D than it did with the 5D2, and the end results viewed at 70-80% viewing don't vary very noticeably between the two.
The crop is taken from a 300dpi 11x14 print...