I went over to the comic shop yesterday, hoping to find some art that would inspire me with character designs I'm working on. I didn't bother looking at superhero books because I wanted something more cartoony, so I focused on indie comics and manga. Every time I saw an interesting character on a cover, I'd flip through the book and think "hey wait a minute, EVERY character looks like that first one."
I'm not going to name any comics in particular, but I had forgotten just how many comics have a single original character design which they then repeat over and over. The exact same heads, features and bodies, just with different hair and clothes. Often that particular design will be kind of interesting and unlike any in other comics, but the problem is I want to see a whole bunch of different designs in one place. So I ended up getting one of those "Meathaus" group sketchbooks. It's full of great stuff, mostly by artists who draw a lot of different characters all the time anyway. So it's got a huge range of designs.
I also picked up "Angura - Posters of the Japanese Avant-Garde" which has a lot of neat title/poster design ideas.