Some really good advice so far. I'd tell you to do it the hard way and spend the time tweaking the mic placement. The best producers I've known for getting heavy guitar sounds have in common that they all spend seriously silly amounts of time tweaking just the right mic placement, angle, etc. I always work with a partner, having him hit chords, lead runs and harmonics while I tweak the mic, then run back and do a listen.
If you have the option, once you've found a mic placement you like, mark the exact spot on the floor and on the cab's grill where you are pointing the center of the mic. I use colored bookmark tape because it's thin, brightly colored and comes off without harming anything. Also write down the exact angle of the mic (as much as possible), both horizontal and vertical.
As to multiple tracking, I like to use three different mic placements, with an optional fourth. Mic 1 is placed 2-3 inches away from the speaker, on-axis, about midway from cone to edge. Mic 2 is placed 2-3 inches away from a different speaker, off-axis, with the mic pointing toward a spot about 2/3 the way from cone to edge with the bottom of the mic angling away from the cab about 45 degrees.
Mic 3 is a room mic placed about 4 to 5 feet high and about 10-12 feet away from the cab. At what angle the mic stand is placed in relation to the cab is a matter of tweaking. Same with the angle of the mic on the stand. This is due to the individual phase problems that are unique to every recording environment as well as finding just the right tone. This mic's placement has to be tweaked while also listening to the other two mics so as to avoid phase noise.
If the guitarist is using an open-backed cab or combo, I use an additional mic. Mic 4 is a flat electret condenser mic that is placed inside the cab if it is open-backed, usually taped upside down against the top of the cab. This mic can capture both a different emphasis of bass tones and can actually thicken up the whole signal by capturing sound waves that are slightly out of phase with the ones captured by the mics on the front of the speakers.
All of this requires serious tweaking, but once you've got it just right, it will yield a much bigger guitar sound per track than simply doing multiple tracks off of the same mic in front of the speaker. You get a wide, full range of frequency response from top to bottom, and you can blend in just the right amount of ambient sound, and that's per track. All four mics can be blended to create a single guitar track. Now when you double it, the guitar begins to sound huge. This is exactly the process I used in producing my latest client who wanted a sound similar to Alter Bridge and Disturbed.
None of this would be possible, though, without developing an ear for tweaking mics. Even if you use DAW's (which I do occasionally), training your ear is still invaluable for getting the best recordings possible.