I'm curious what type of lock everybody is using on their bike. I'm thinking about getting a more compact lock than my big chain and big lock and I'm trying to get an idea of which lock is the easiest to install/remove and the ease of transporting it.

I've seen people using the locks that attach to your front rotors. If you buy one of those, be sure to attach that strap to your handlebar to remind yourself that it is locked. I've heard stories of people forgetting and trying to ride away with it locked.