I had an old sketchbook in one of my bags that I don't really use anymore. Part of the reason is that it is a bound sketchbook, which is fine, but I've switched to the ringed book, which I think makes it easier to work with. Additionally, my ringed book is, I believe, 11" x 17"; this older one is an 8 1/2" x 11" book, which isn't bad, but now I can do full-body illustrations without having to forgo detail and/or splice two images together, which I think can be a pain in Photoshop, regardless of how well everything matches up on paper.
Anyhow, the following are some of the better sketches for you to check out; a lot of them are completely unfinished, so keep that in mind. There are a couple of non-comic ones towards the bottom, too.
Clockwise, from left: Batman, The Joker, Commissioner Gordon, Harley Quinn
Harley Quinn (This Harley, as with the one that preceded it, was a sketch for a comic sequel to The Dark Knight.)
Batman (This was part of a Project: Rooftop-concept redesign, as are several of the following Batman-related drawings.)
Jim (The Office)