I'm also keen on not just getting a fluffy self-education - I want to REALLY understand the underlying principles of computer science in a way that just picking up a book on Python would probably not provide.
My current plan is to work through SICP (I picked up a hard copy from the MIT Press book store in Cambridge), and then proceed on to Introduction To Algorithms and other subjects.
Is anyone interested in being a learning partner? It would be great to either have someone who's going through the same process or who has done it before and wouldn't mind sharing their worldly wisdom with a newcomer :-)
EDIT: I put together a wiki for notes / solutions to exercises... http://sicpgroup.pbworks.com/
I'd love ideas on how to structure a group for this to help everyone stay accountable.