you shouldn't need a compressor for guitar recording IMO. you should be able to achieve the tone you're looking for through mic placement and maybe a little eq'ing.
what dynamic mic are you using? sometimes using more than one mic can give you a fuller tone, either using different types of microphones or by placing them differently (on the cone/voice coil, off axis, mic'ing the back of an open back cab, etc)
and how are you recording, with your computer?