I've been playing in a band for a while and just kind of made it up when I did the setting on my amp. I suppose I wanted something close to my acoustic which I learnt on.

I play mostly rhythm guitar and use a Tube Screamer for some extra kick, but my settings are:

Bass: 7
Mid: 6
Treble: 7
Gain: 1

My question is: Is my low gain a problem? Am I losing something from my sound? Will it make my music too strummy?
what amp is it?

gain set on 1 for a 5150 is going to be different then the gain set on 1 for a fender twin?
Ahh yes a little more info. My amps a Peavey Classic 50 and we play: Indie with punk edges. Pixies, Kings of Leon, Strokes etc
it's fine.. i play punk and use the clean channel only.. i use overdrive on it too..

Honestly, it's all about whether you like it or not. Try experimenting with it... play something how you have it set. Then start raising the gain and play again... until you find the best setting for you. If it turns out that you like it better with gain on 1 then that's great. If you prefer gain at 4 or 5 or 11 then that's great too.