The following are my current favorites! I check on them regularly, based on how often they update. You should, too!

Achewood	This started out as a strip about what a guy's stuffed animals were up to when he and his wife were out. It gradually became a strip about two cats with stuffed animal friends. Onstad has a gift for dialogue and characterization, and can really set up a joke. I'd start by reading the archive from day 1, to get into it.	Almost daily
A softer world	My friend Jeff compared these to haikus, and he is not completely wrong. A gifted writer and photographer write strips that sometimes seem too beautiful to be funny, but after a second you realize you've just read some really twisted humor.	About twice a week
Perry Bible Fellowship	The art style varies dramatically, depending on the individual strip. The writing is laugh out loud hilarious, and brilliant to the point where you are amazed.	Sundays	(can't link directly)
Dinosaur Comics	I've loved em since my friend Redlami told me I should check them out!! Click here for my pictorial review.	Daily
Wondermark	If someone on the internet wrote a strip just to make me happy, it would be this guy. The nineteenth century art that I love, and an evil mind writing the text.	About twice a week
xkcd	I wasn't planning on updating this review thingie, but I found this hilarious nerdy joke strip by a NASA Physicist and had to share it with you!	Thrice a week

I also highly recommend the following! I check in on them periodically.

Married to the Sea	Similar to Wondermark in feel - this is a single paneled strip, in which old illustrations are given new captions. Often hilariously.	Daily
A lesson is learned but the damage is irreversible	Very lush art, and unusual writing. Not laugh out loud funny, but you love to enjoy it.	About twice a month
Spamusement!	This guy takes the subject lines of his spam and illustrates them. He can't draw well, technically, but his style is perfect for his jokes.	Intermittent
User Friendly	There are lots of computer-geek comics out there, for obvious reasons. This one is my favorite.	Daily
When I am King	This was a continuing story that is now finished, but there are enough strips that you could look at one a day for a long time, and remain amused. You scroll horizontally and look at some art that is not as simple as it appears, attached to a story that is not as wholesome as it seems.	Never. I lied about checking it periodically

There are other web comics I've found that I like, but let's leave the list right here, or we will be here forever. If you want a big, annotated list of web comics, here is a good place to go.