I never actually registered to vote until about 4 years ago so for me, this is all still new and exciting. Sure, my one little vote is just a drop in the bucket, but voting encourages me to stay up on all the little local issues, know who's running for what - what they stand for, what they vote on and what they've promised for our communities, etc.
I started voting when my kids were learning about the election process in school and started asking me why we'd never gone to the polls. They went that year with Daddy, but then started telling me that I should lend my voice as well. So I registered and the next year started voting - now the kids look forward to reading about the candidates, discussion propositions and political issues - it's become a whole family thing.
We all have different reasons for voting/not voting - but IMHO the best thing is that we have the CHOICE to vote - or NOT vote. I can't imagine how I would feel if it was against the law NOT to vote as CJ stated. Ack! I think I might have a completely different outlook on the situation in that case.