So many possibilities here, so I'll share some of my experiences/preferences ....
In the studio, I like to double-mic guitar cabinets with a large-diaphram condesor (a Nuemann U87 is my favorite), and 1 dynamic (the Sennhieser 421 is my favorite here). A lot of people go nuts with phase-alignment between the 2 mics, but your ear is the ultimate judge. Whether I blend them immediately or record them seperately and blend in the mix will depend on the number of other things I have to record, but generally I will find the tone I like between the 2 mics and commit that tone to a single track. Distance is around 3-5 inches from the cabinet.
For live, I will usually go with a dynamic ... the 421 if available, but ususally a Shure SM57. Again, about 3 inches form the cabinet.
In both cases, I prefer pointing the mic at the edge of the speaker cone rather than the center, as I find the tone somewhat tighter and less "woofy". That applies regardless of whether the tone is clean or distorted.
As always, that is what works for me ... your milage may vary :glasses10: