There are loads of threads on this here.
Currnetly just use a pair of alto TS212s, a behringer 12" sub (don't bring that everywhere) and we put the 3 vocals, bass drum (although not much if not with the sub), sax and guitar through it, although the guitar is only to spread it around a bit more. Flat out it works fine but there isn't much spare. Just picked up a RCF Evox 8 to see what that is like.
Don't have any monitors, me and the drummer are in-ears., the singer is always out the front in front of the PA and the guitarist seems to cope ok.