Re: learning a second instrument
Learning to read and learning theory can compliment each other well; particularly when playing the Piano - if that is indeed your goal. I've spent the last term at University learning Music Theory and I found it very useful. I'm not a snob either, I'll listen to anything, but sometimes learning just a bit of theory is very useful because suddenly things make a bit more sense.
You ought to learn to stick with another instrument as well! I think there's a certain mindset amongst drummers that they become very 'instrument focussed' and only learn about drums and drumming rather than music. I've noticed it happening to guitarists particularly as well - but mostly drummers. Learning a new instrument and being able to appreciate it - even if you're not particularly good - is important to break this mindset. Go for it.