Besides the 555 timer projects and the regulated power supplies, what would you guys recommend?

Thanks!

 

Try an op-amp audio amplifier, or an oscillator circuit. Both can come very useful, and both will teach you a lot.

 

Also decide what medium you want to use. Op amps are extremely easy, they are the logic gates of analog, while transistors are very old school and a bit harder to understand. You have to learn both eventually.

Another idea is something like electronic dice or flashers, both using regular digital gates.

 

Pick up a few of Forrest Mims III Mini-Notebooks.
His website:
http://www.forrestmims.com/
The mini-notebooks:
http://www.forrestmims.com/engineers_mini_notebook.html
Volume IV has lots of information all in one place; makes for a very handy and compact reference.
Volume I is jam-packed with fun (and useful) circuits for you to build and try out.

Radio Shack started carrying the Electronics Learning Lab again. Forrest designed the lab and wrote the two notebooks that come with it. It occasionally goes on sale.
http://www.radioshack.com/product/index.jsp?productId=3814337

 

Yes!!! I loved those books! I also liked the learning labs, both were/are very cool.