I am often asked about courses after COS 109 -- courses that go deeper into CS or other aspects of computing, or other courses about technology and society. Here are some suggestions for Spring 2012. I don't have first-hand experience with most of these, but I know and can recommend the people teaching them, though of course your mileage may vary. I'm happy to talk more about the courses, or help connect you with better sources of information than Course Offerings. And suggestions for additions to this list are welcome.
COS 126, General Computer Science (QR). This is the basic intro course for CS majors, the certificate in applications of computing, the SEAS programming requirement, etc. If you liked the more technical end of 109 and found the programming more interesting than terrifying, 126 is a good bet; it's definitely the best way to take the next step if you think that CS or the certificate might be an option, or if you just want to try the next course.
EGR 277, Technology and Society (SA)
ELE 386, Cyber Security
ELE 491, High-Tech Entrepreneurship
AST 203, The Universe (QR)
CBE 260, Ethics and Technology: Engineering in the Real World (EM)
CEE 262, Structures and The Urban Environment (STL or LA)
TRA 305, Imagined Languages (HA)
MUS 314, Computer and Electronic Music through Programming, Performance and Composition (LA)
As always, there are a bunch of interesting freshman seminars as well.