Time signature usage

I don't read music, but I can tell you that when I use programs on my computer to write music, I will often find myself being blocked from going further until I assign the correct time signature to the particular bar I'm working on at the time, and sometimes I will end up with something that sounds to me like it could fit a smaller time signature perfectly, but the program itself won't allow it.

As some of the guys with degrees in music theory will also tell you (when they see this thread): Most music is organized in groups of 2 or 3 beats. Of course you can break every complex signature down into such groups, and usually a 3/4 piece will have a grouping of 2-2-2, while one in 6/8 will have 3-3. Personally, in Rock music I usually listen to what bass and snare drum are playing. For example, to tell 7/8 from 7/4 you can count the bass/snare drum notes and compare the pattern to a typical rock beat where the bass drum would be on 1 and 3, and the snare on 2 and 4. As a specific and well known example, if you listen to Pink Floyd - Money, you'll notice that within one sequence of 7, the bass drum plays on 1, 3, 5 and 7, and the snare drum on 2, 4 and 6. That's much more consistent with two bars of 4/4 with the last beat ommitted, than with one bar of 4/4 with one 8th note missing.

As a musician who can read music, I've sometimes found it a bit unusual when there are certain time signatures used instead of others on sheet music. I thought this would be a great place to discuss it.