As @pcake said, volume wars are usually caused by everyone having their speakers pointed in a direction that they can't hear themselves. If you have your amp/cab on the floor blasting the backs of your legs, you'll be the only person in the room who can't hear you; likewise for everyone else. If everyone has their amps/cabs on stands (or something) pointing at their own ears, everyone will hear themselves much better and will not need feel the need to turn up. My band had this problem for awhile, and once we rearranged our gear we discovered we could play at much lower volumes -- and keep it there.
That said, I agree with those who say that even then a single 1x12 with any number of watts probably isn't going to be enough. If you already have another (8-ohm) cabinet, it would be silly not to try using them together -- which will be the same as a comparable 2x12, 4-ohm cab, per your previous question -- to see if that's enough before buying any new gear.
That said, I agree with those who say that even then a single 1x12 with any number of watts probably isn't going to be enough. If you already have another (8-ohm) cabinet, it would be silly not to try using them together -- which will be the same as a comparable 2x12, 4-ohm cab, per your previous question -- to see if that's enough before buying any new gear.