Some suggestions, some of which will probably be required reading, not in order of importance:

Modern Architecture Since 1900 by William J.R. Curtis

European Architecture 1750-1890 by Barry Bergdoll

Modern Architecture by Alan Colquhoun

Programs and Manifestoes on 20th-Century Architecture by Ulrich Conrads

Architecture and Design, 1890-1939: An International Anthology of Original Articles by Tim Benton

"Dear Theo"

Or better yet  "van Gogh's letters"

A Pattern Language, Christopher Alexander

Morality and Architecture, David Watkin

@jw468 Thanks, been reading the Colquhoun already, on the recommendation of a Cornell professor I know. Just started reading In Praise of Shadows by Tanizaki last night.

@EKE A Pattern Language;  classic. Have had that on my shelf for years and referred to it many times. Thanks for the suggestions. 

1000 plateaus.......Deleuze and Guatarri

Sounds like you already have a pretty good grasp on the standards. I'd also add:

Modern Architecture: A Critical History by Kenneth Frampton

The Eyes of the Skin by Juhani Pallasmaa

And my new favorite,
New Nordic: Architecture and Identity by Kjeldsen, Schelde, Andersen and Holm

Architect?: A Candid Guide to the Profession, by Roger K. Lewis.

On Bullshit by Harry Frankfurt. 

you might as well jack off into a moist towelette. 

Learning from Las Vegas 

Thanks everyone. I'll start spending the books budget now while I have more time to read them. Good thing I finally realized that I need reading glasses, and got them. 

@geezertect Got that right here next to me. I've been reading that off and on for a couple of months now and, from what I can tell, it should be required reading for anyone considering the profession. 

Gourmet Dumpster Diving by Al Jenkins

Anti-Architecture and Deconstruction, Nikos Salingaros

It's a short article, but a must read.

Dear Architects by Annie Choi

Leave architecture books for architecture school.  Read far and wide on other topics that interest you.  Expand your mind.  You'll be reading architecture books as long as you're in this profession.

Book titles with "theory" or "ism" are ones you should generally avoid until you are forced to read them for school.  The are generally impenetrable gibberish.  No sense in polluting the stream until it's absolutely necessary.

Tom Wolfe, "From Bauhaus to Our House". A hilarious send-up of every black turtle-neck wearing egomaniacal architect or professor you will encounter on your journeys.

Becoming an Architect, 3rd ed.

http://www.wiley.com/WileyCDA/WileyTitle/productCd-1118612132.html

101 Things I learned in Architecture School, by Matthew Frederick

Holy fuck! Colquhoun? Deleuze? I imagine that sort of stuff would have put me right off the idea of entering architecture school... I agree with the geezer over there, avoit all that gibberish while you can!!! Don't get me wrong here... Frampton's Critical History is a great book if you want to get a comprehensive view of the genesis of modern architecture... And I think Learning from las Vegas is pretty clever, certainly amusing and useful if you want to understand all that nonsense Venturi goes on about... But I wouldn't recommend them for someone who has yet to cut there teeth on the subject...

I would personally go for stuff like...

Experiencing Architecture by Steen Eiler Rasmussen

Architecture as Space. How to look at Architecture by Bruno Zevi

and... (although it only focuses on classical architecture)

The Classical Language of Architecture by John Summerson

Learn to walk before you run!

You could just skip school if you bought Architectural Graphic Standards and then while practicing read 1000 plateaus and you would pretty much be on top of it.....

Didn't you watch Goodwill Hunting ? Just get a library card.

Thanks for all the suggestions, everyone. As for the idea that I should expand my mind before sequestering myself in the church of architectural education, I'm going to ignore those suggestions. No offense, I hope. I've been out of college for 20 years, and have been reading and experiencing widely ever since. I'm not too worried about approaching the program with a limited and jaded mind or a narrow focus. I'm coming to this with the mature interest that comes from being truly ready to begin the study, and so even the arcane and confounding texts are interesting to me. (We'll see what tune I'm whistling in a couple of years, but for now I'm devouring these books.)

Remember:  Great hobby, lousy profession.