Yeah, that's the main reason I've thought of base 12 and base 30. 2, 3, and 4 are very common numbers, so duodecimal or even sexagesimal would work well with that. I think the main reason 5 is so common is the decimal system and our fingers. With that and number of characters, I like duodecimal the best.
Not that I'm saying that we should change. I like decimal , too. It would be virtually impossible, anyway. Quag is right about teaching it, though I've read that ancient Egyptians counted in base 12 by counting the finger knuckles with the thumb.