I'd never bothered to shift tracks against each other to line up the waveforms if they were slightly out of phase with each other, but I was fucking with an old mix last night where I'd used two mics on the rhythm guitarss, and for kicks tried to line them up - they weren't badly out of phase at all, but you could hear alittle phasing whenyou collapsed theminto mono.
Wow. Subtle, but oh-so-nice. I'll definitely be doing this from now on whenever I use more than one mic - it's not really an excuse for just getting it right in the first place, but it's fucking hard to go from 99% there to just right when you're positioning mics, so this is a nice little shortcut.
There's a GREAT article on this in the current issue of Sound On Sound. My bandmate picked it up and had us all read it, since we're just a couple of weeks away from tracking guitars on our record.
There's also an excellent article on the recording and engineering of AC/DC's new record, emphasizing a "simple is better" approach.