I currently use a 1x12 combo..... well, 2 of them - but I A/B them so they aren't used at the same time. I have the Roadster combo and a Vox AC30 1x12 combo. Before that, I used 2x12 combos for a couple of years and before that I used a couple of 2x12's and sometimes a 4x12 in conjunction with one or both 2x12's. To be honest, the 1x12 sounds just as good out front as 2, 4, 6 or 8x12's. In all reality, if you are in a "gigging" band then the lower the stage volume is the better the mix can be out front and it's hard to control your volume with a 4x12 on stage. Even if you're using a 4x12, you're only putting a mic on one speaker.... so in theory, a 1x12 will sound just as good through a PA as two 4x12 cabs.
As for bass response, you're gonna hate part of this comment..... through a mic, a 1x12 or even a 2x12 will still have the same bass response as a 4x12 but it won't feel like it on stage....and actually, you really shouldn't need a lot of bass. If you use too much bass, you start treading in on the Bass players tonal pallett and your amps bass gets burried in the mix...... or when you go to take a lead break (if you're a lead player), the bass disappears and leaves a big gap. So really, you don't need a lot of bass.. It's more for the player, but I bet any soundman will dial out some bass if your tone is too bass heavy.
So to answer your question, a 2x12 will be just fine. It'll give you a fuller sound on stage than a 1x12, but won't be as loud as a 4x12. But in all actuality, a 1x12 is enough.
hope this helps.
Oh yeah, I play everything from country to hard rock (Keith Urban, Brad Paisley and Johnny cash to Puddle of Mudd, Creed, Metallica, Alice in Chains, Shinedown, ect...)