First, the usual wisdom is that dynamic mics are better than condensors for miking a guitar amp. They can take the sound pressure levels better, and the sound from guitar speakers is lo-fi enough that the better frequency response of condensors is not a factor.
Second, stereo is a way of presenting recorded sounds using two speakers that somewhat emulates the dimensionality of hearing the original sources as if they were really in front of you spread out in some way. As a rule of thumb you should record everything to mono tracks, then use the pan controls in the mixing phase to place the tracks in the stereo spectrum. One exception is when you are trying to capture as accurately as possible the sound of an acoustic instrument in a real space. This is usually a very specialized and pofessional endeavor, and not a typical home recording scenario. Another exception might be with a drum machine, if you have already programmed and mixed the drums and they sound exactly the way you want them out the stereo outputs -- then there would be no harm in recording them straight to a stereo track and just playing them back that way. But if you plan to isolate all the parts of the kit to separate tracks so that you can have complete freedom during mixdown, then record mono tracks.
