This was the first RPG I bought as a kid, not because I cared about RPGs, but because it said Robotech and had awesome pictures:

It was from this book that I learned that Robotech was made from 3 Japanese cartoons, which kinda blew my mind. I read everything I could about all the characters and mecha and kind of glossed over the RPG stuff. I bought some more of the books for the pictures and info. I eventually even played the game with some friends. The rules system totally sucked ass and a lot of the information in the books was just wrong, but I loved those books. They had about half original Japanese line art and half artwork from some American dude named Kevin Long. The one with the most Mospeada line art was this one:

The next anime RPG I bought was Bubble Gum Crisis.

Again I bought this for the pictures and info. Tons of sweet, sweet line art. Mecha and characters. I played this a couple times too but my friends weren't into it. The rules system was far better than Robotech's. I had another sourcebook for the game as well.
My friend rescued this one for me from a library's trash:

Again, this was awesome for the line art and information. I never knew how much there was to know about Tenchi Muyo and all the different powers and planets and organizations. Who knows how much stuff was just made up, how much was canon, and which info came from which continuity (OAV, TV, movies, doujinshi). It was an awesome book though, chalk full of info. Looked like a pretty good game, too, but I never got to play it. I think it used the Big Eyes Small Mouth system.
I think I may have the El Hazard RPG hiding somewhere but I'm not sure.
I just bought this out of curiosity:

All I know is it uses the Silhouette system, which is used by the Heavy Gear games. I hope it has lots of cool line art. We'll see.