Editing on a home PC should never involve huge, uncompressed files, because it slows down your system enormously, and thereby your creative real-time workflow. But the T2i’s MOV files are already heavily compressed, so you might be able to use them as they are. Alternatively, you may create your own “offline” material, by converting all the mov files to smaller resolutions with more compression (a frame-by-frame JPG compression is also better for editing than the motion based MPG, H264 etc).
Then you have to re-create a lossless master in After Effects (“onlining”), to do your VFX and grading.
If you worked with the original files in Vegas, you should be able to export a lossless master from there, without any quality loss. Just make sure there’s no de-interlacing or anything being applied to the clips in Vegas. Double-check in After Effects that your Vegas render is a perfect match to the original files.
If you used compressed files to edit in Vegas, you’ll have to re-create the film in After Effects.
Typically I do this manually clip by clip, because I’ve always been to lazy to check out the alternatives, and I never trusted a Vegas-AE solution to be stabile… but that’s maybe just me being old fashioned. And it feels like a stupid thing to do, because it’s so mechanical that it SHOULD be automated. I think you can automate it easily from Premiere to AE (because they’re both Adobe), but I don’t think there’s an easy way from Vegas to AE. There’s a script out there called Automatic Duck, which should do something along those lines, but I’ve never used it…