Ryan Patch is right that there is no added bit-depth, color information, or resolution added to a file that you transcode. The file can ever only be as good as what you capture it on originally. Period.
However, the reason transcoding is necessary is that not all apps work like Premiere Pro. Not all apps can just play any media. So if you plan on doing more than just editing in your timeline I encourage people to transcode. If you’re doing color correction, as you state, I would highly encourage transcoding beforehand as most color grading apps won’t deal with h.264 media (Resolve kinda does, but not to where I’d rely on it as a workflow). Apple Color won’t. Speedgrade, assuming you’re running CS6, will transcode your footage to DPX files for color grading.
Point is if you don’t have to transcode don’t. As Ryan says, it takes more space and time. But if you plan on doing work in other apps that aren’t Premiere Pro then I would transcode to save yourself the headache that comes from other apps not playing well with a heavily compressed format – h.264.
Ryan Holmes
http://www.ryanholmes.me
vimeo.com/ryanholmes