Thanks for this topic: ++. You've put it better than I, and saved me the trouble of asking myself. I'm in the same boat, only probably not so advanced.
in reply to Recommendations for a self-taught Perl programmer
The only thing I would add to the above most excellent advice is, find a mentor. If there's a particular ninja in your group whom you really admire and with whom you naturally seem to "click", by all means approach that person and ask if he or she might consider some sort of formal arrangement. The advantage of that is, you have someone who knows how Your mind works, and who can suggest ideas and examples to you from things you are both very familiar with in your own work environment. It needn't be so formal that it takes up tons of time for either of you-- more just, "I'd like your help and advice, and I'd like you to feel free to jump in and suggest new directions I could take my study." You, of course, would still be doing most of the work-- you'd just have somebody to watch your back.
And I third (or whatever we're on by now) The Pragmatic Programmer. If only to point out how much I still have to learn, it's been great. And the writing is very accessible and clear.