I nearly always use 2 mics, in my case an sm57 (or 421) and a ribbon (I like ribbons) right in front of the cone, depending on what sound I want I sometimes move it in and out slightly and sometimes slightly off to the side, I sometimes use a SM57 and a large condenser. He is right, most times you can get the sound you want by blending the 2 mics and not even touching the EQ, if possible I record the 2 mics to separate tracks so the decision can be made later, if not make the decision while tracking. The trick is to get a good guitar sound on the amp first.
I very rarely use a room mic for electric guitar.
Alan.