Frazz by Jef Mallet
I really like Mallet's graphic style. While it is very disciplined, it looks loose and sketchy, almost at times like Bill Watterson. His characterizations (both visual and dialogue-based) are great. I especially like Ms. Olson, who (no doubt unfairly) reminds me of countless teachers of my youth.
Yehuda Moon and the Kickstand Cyclery by Rick Smith
Yehuda Moon is an online-only strip and is subscription supported. Judging from the amount of comments on a strip on any given day, he has a strong readership (and I hope that is reflected in the subscription ranks.) There are a lot of cyclist "insider" jokes in this strip, and casual recreational cyclists might not get all of them. But you know, I've known guys (especially in Austin, Texas, where I used to live) who worked in bike shops who were just like Yehuda Moon.
Sprocketman by Louis Saekow