use to work for a mobile recording truck, our typical setup was this:
6-10 mics.
two sm57's on stage with short stands (getting as close to head height as possible to pick up the crazies in the front row of the show)
on the sides of the stage we would put a pair of mics per side. one shotgun and one small diaphragm condenser. the condensers pointed at foh and the shotguns were pointed in different places depending on the venue.
sometimes we would put 414's at foh facing the stage, sometimes not. depended on the venue. and in large venues or arenas we would put another pair of shotguns pointing away from the stage at the foh booth.
on a minimalist setup I would say the pair of 57's on stage and the small diaphragm condensers on side stage can get you a good crowd sound.
but all of this depends on the crowd, if they are not lively, then the type of mics you use and where you put them wont matter. as for samples, not a fan. never captures the feel of a crowd that is pumped and into a show. but if you must you must.
(just another note) when mixing live performances, don't ever mute your crowds. keep them in your mix wide open and eq as necessary to make them sit well. it helps keep the "live" feel going in the mix. and when you need to push crowd, push it, but don't unmute and mute and unmute and mute. trying to get a live performance to sound like a "record" is pointless in my opinion.