I've a few that I check out regularly. Lately, I've been perusing the archives of Saturday Morning Breakfast Cereal. Here's an example of Zach Weiner's work:
I also like the humor of Married to the Sea, a juxtaposition of old catalog and historical images with irreverent captions by Drew and Natalie Dee:
Max Cannon's Red Meat isn't a web comic, as it originated in print, but I enjoy its macabre humor enough to mention it here:
What is your favorite web comic?