I have the feeling that you're going to love Twitter, but it's also true that microblogging isn't for everyone. The constant pressure to answer the canonical Twitter question "What are you doing?" may simply become too much after a while. If taking a short break doesn't help (I'm talking about a few days or even a few weeks, not a few minutes), then you can walk away and move on with your life. You could opt to let your account lie dormant (it is, after all, free), but if there are updates
you want to get rid of, or if you don't want new people to follow you, then you should delete your Twitter account.
Of course, it could be that you love the whole Twitter thing, perhaps even to the extent that you've created multiple Twitter accounts. Lots of people juggle multiple Twitter identities (I have two, myself ), but it requires lots of logging in and out, and lots of extra work updating and maintaining each account. If it all just gets to be too much, you might want to delete one or more of your accounts so you can finally get some sleep at night.