I've been using Calorie Count to track my calories since July. Some of my friends really like MyFitnessPal a lot, too.
I have a MapMyRun account and I do like it but I found it to be a pain logging workouts in multiple places so I haven't been updating it as much. BUT, I really do like it's features for creating routes so I'll keep that account around.
I've recently discovered Tumblr blogs. I mean, I knew they were out there but I just never quite got the point of it until I started following a few Fit Bloggers on there. My favorite is FuneralForMyFat (tons of good advice there) but I follow a good half dozen or so.
Blog wise I really like Roni's Weigh, The Sisterhood of the Shrinking Jeans and Skinny Taste.