As the question says ^ Also, please give a reason as to why it is your favorite tracker. You don't need to use it everyday, you just need to be a member There's no second places, no thirds, no runners up. Just pick ONE tracker; your absolute most favorite.
Mine would be PTN because their IRC is always active and lively, they have a lot of interesting features, and the overall community feeling is pretty large there. The no-ratio doesn't hurt, either