Hi,
Some background first-> I am new to programming and have discovered it rather late in life; Like many hobbyists, my introduction to the subject has been through php/jquery (yes, i know the popular mood around here... they-are-not-real-programminng-languages ;-) ). I like to believe that I am reasonably competent at what I do in my other life and this developing addiction to coding has taken a very heavy toll on my professional prospects.

This is the question:
What programming languages next? (No plans to ditch php in the immediate future, that will involve rewriting much of my code)
Any absolutely essential books I must read?
Is it necessary to join a college/university course?
Do I need to ditch my other profession to continue serious learning?

My goals are:
Develop a solid understanding of the science and art of programming.
Continue to work on my own web application (Hands on learning suits me best)

I am something of a generalist interested in everything from UI to database performance