I dumped Carbonite after the first day.

My favourite is Backblaze. Very simple client software that works very non-intrusively. Backups everything (except systems files) by default, good policy. But only keeps files around for 30 days after you delete them from your hard drive.

For more bling, my next fav is Crashplan. Lots of features and generous storage policy (nothing gets deleted ever). But chunky client software gets in the way sometimes.