ProRes Lt or normal

LT and regular are very, very comparable in terms of image quality. In a quick test I did taking both LT and regular though our typical post pipeline (editing, basic color correction, laying off to HDCAM, exporting to QT, WMV and H.264 for the web) the end products looked the same. If you are starting w/higher quality material and are doing a lot of post processing ProRes regular will hold up better, but LT is surprisingly good looking for being the 'lite' version.

Lethal

 

Regular will retain fidelity through more compression cycles.

But as a general principle, codec choice should be based not on how much quality you begin with, but rather how much you want to retain. A dirty VHS image would be more difficult to compress than a pristine DVD image. For the image not to visibly degrade, you'd need a better codec/higher data rate for the VHS than for the DVD.

 

^This.

If you're not doing heavy manipulation, LT will look just as good. Especially if we are talking web and DVD delivery.

 

Are you using the EOS Log and Transfer plug-in for FCP and the T2i?

http://www.finalcutuser.com/?p=1829

 

The main reason for differentiating the ProRes flavours comes down to what you are using the video for.

ProRes Proxy - For offline editing - when drive space is an issue. This is designed to be recaptured later at higher resolution.
ProRes LT - For DVD, the web or television news.
ProRes - For broadcast television.
ProRes HQ - For broadcast television and films shot on hi-end 10Bit camera's (RED and above).
ProRes 4444 - For graphics work and hi-end films.

 

Bit depth has nothing to do with it. All ProRes codecs are 10-bit apart from 4444, which is 12-bit.