I love Order of the Stick. It is a fantastic comic that all D&D people should read. It's awesome. Definitely worth buying the books.
I play a lot of D&D, too. It's often the case that I'm inspired by our adventures to work up some comics in the OOTS-style because it's a great style and I've gotten the hang of doing OOTS-like things in Inkscape. Inkscape is a fantastic vector-based drawing program available for a variety of operating systems. It's Open Source software at it's best.
Following is a list of comics I've done. The names of the comics match the names of the D&D groups I was in that they derive from.