reading definately helps. I've been on both sides of this. On one hand, most of the playing I've done in the rock, pop, country genres have been entirely by ear. However in jazz I've often played with charts. It's important to note that drum charts are usually NOT note for note parts. It more or less tells you the form of the arrangement and gives you key hooks and rhythms to play. I studied music in college so did a lot of reading. The skills I have developed for reading have been invaluable. Once I got called to do a tour with an artist from Sweden here in the states, and got the call literally the night before the first show. They basically said, "can you be on a plane to San Diego tomorrow morning for a show tomorrow night?". I had never heard this artists material before. So, I really didn't have time to try and memorize his stuff. I downloaded all his stuff from itunes, and was listening and WRITING drum parts on the plane. If I didn't have those reading (and subsiqently writing) skills, there's no way I would have been prepared, because in this case I was playing with backing tracks that already had drum machine in it. So, I had to play every kick drum note, snare note, etc... exactly as they were on the record, otherwise it would sound off.
As far as being able to read regular music (ie treble and bass cleff primarily), reading scales, chords etc... its not something that you'll often use directly as a drummer, but nonetheless, understanding that stuff can come in handy. For example, knowing the difference between major and minor modes can make a difference in how you "color" songs. Also understand what a 1, 4 and 5 chord is will help you understand how to frame the form of the tune.
Lastly, remember that you're a "musician", before you are a "drummer", and thus learning ANYTHIING having to do with music, whether directly related to drums or not, is always good.