Let's see what I can remember!
The Adventures Of Augie March (1953) - What Brian Burks said--this book has a stunning panorama and breadth to it, but I didn't really care that much about what happened to any of the characters. You should still read this as it's one of his most revered works (or at least it used to be--Bellow doesn't seem to get as much attention as he used to!)
Seize The Day (1956) - I found this short book--the first Bellow I read--way too blunt, but in retrospect I was hard on it. It's a book to read when you feel like a crappy failure, and hey don't we all at some point?
Henderson The Rain King (1959) - I think this book ranks the highest of Bellow's works on the Modern Library Top 100 20th Century list, which I refer to a lot for some reason even though it's obviously a miserably flawed list (there's like two books from past 1980--Ironweed and Midnight's Children, and that's it.) I don't for the life of me remember why it's the highest ranked, because I don't remember what even happened in this book. I seem to remember it as being a sort of parody of people who go on spiritual journeys.
Herzog (1964) - Heavily psychological, this story about a Jewish intellectual plagued by relationship woes is the kind of thing I typically only admire from a distance, which I did--it's a well written book--I just have nothing to add much about the subject matter. It's one of his more acclaimed books, so read it. I seem to recall finding one of the female characters, the ex-wife, portrayed far too cartoonishly and shrewishly. Note: I didn't know what the word "herzog" meant (German equivalent of "duke") until I read this book.
Mr. Sammler's Planet (1970) - I remember this one better because I'm fascinated by what major novelists were writing at the end of the 60s revolution and this one starts off with another Jewish intellectual character...BEING CONFRONTED BY A BLACK PIMP ON THE STREETS, who I think threatens him with a knife or something? Gawd that's a bad note to start on, but this was otherwise a good book, about the intellectual being dizzified by the changing times. I dunno, I like Rabbit Redux best of the Rabbit books too, so neener neener.
Humboldt's Gift (1975) - Bellow won awards, for, like, all of these books, and again, I can't remember a DAMN THING that happened in this one though I remember it being fairly easy to read, if a bit longer than his others. Jesus, I'm really sorry to sound this stupid--I read all of these books, I swear! I had to look this one up to even remember the names of the friggin' characters in it, or what it was about--I really might as well not have read it at all! What was I DOING at the time?!?
Ravelstein (2003) - Bellow wrote this book at like age 85 and it's my favorite of his books. An unusual choice yes but I was fascinated by the story of Allan Bloom, who if you don't know who he was, wrote The Closing Of The American Mind in 1987 and went from being a professor to a huge literary celebrity/public intellectual overnight. His book, if you haven't read it, started off with an enormous conservative trashing of the modern university, Political Correctness, leftist political slants in classes, and youth culture, claiming basically that kids were being brainwashed by MTV and Mick Jagger (that's who he goes after the most) and the like, then goes into an enormously lengthy history of American philosophical thought and its roots in Weber and whatnot that I can't remember the details of for the life of me because it was like 100 friggin' pages long. Bloom was also a closeted homosexual who died of AIDS in 1992 (even though a significant portion of his book was about trashing youth sexual habits) and didn't tell anybody and I think this book is where the public found out about it? Ravelstein is Bloom and the narrator of the book is Bellow using a pseudonym, it's a pretty readable dramatization of their relationship. It's also short.
Bellow is thus not really one of my favorite writers, but he wrote some good stuff. Maybe I'd like him more if I were Jewish but I liked Philip Roth a LOT and Roth was one of the whiniest Jewish dudes ever (Bellow isn't terribly stereotypical, mind you.)