If I were recording for a cd, I would always record a live mic'd amp and a DI'd track for later reamping. I'd be doing this for flexibility, in case I wanted to completely change the tone of something. This is the biggest benefit of reamping.
The second reason is so that I can record late at night. I can record endless DI'd takes, monitoring through my PODXT Pro until I get a performance I am satisfied with using headphones and not bothering my wife while she's trying to sleep. I can then reamp the track the next day as loud as I want because instead of recording endless takes, I only have to reamp the track a couple times (honestly, mostly just once with my main amp - I know how to set it to get what I want) to get the tone I want.
If you listen to my clips, some of them were made with a live mic'd amp and some were reamped after recording a DI'd track and monitoring my PODXT Pro so I could hear a real guitar sound. What is cool about mine is that almost every one was made with the same amp with the same exact settings, whether reamps or original mic recording. I bet you cannot tell which tracks were a live mic'd amp and which were a DI tracks that have been reamped. The reamping process works well enough that you cannot tell the difference from an original mic'd amp performance.
For all the reasons I mentioned, reamping kicks ass...
BTW - I use the original REAMP (
http://www.reamp.com) and it is brain dead simple to use and sounds great!
Steve