I use the transpose occasionally as a tool, not a crutch. For instance, if I'm doing something orchestral and I need a harp flourish in B, I use the F# pentatonic and transpose it to B. In other words, all black keys; that way I can just slide along the black keys like a harpist would strum across the strings, rather than try to play a B pentatonic scale that fast, which would be impossible for even Art Tatum.

Also, it does sometimes come in handy to go either 1 semitone above or below, but I can't go further than that, and even that I only have done very infrequently.

Regarding capos, it's a totally different animal. For one thing, guitars don't have white and black keys, so G sharp as a bar chord doesn't feel any different than A as a bar chord. Not so with piano. Of course, what makes the difference is the open strings, which is an excellent reason to use a capo. I'm trying to get voicings that require open strings, but in a key that doesn't permit open strings, so I put a capo on and suddenly I have my open strings in that key. But that's mostly for country and bluegrass and folk type stuff. If I'm doing a bluegrass song in Bb I need my acoustic guitar to sound like he's playing all the open G licks. I can play jazz tunes in Bb all day long without a capo, but you can't rip convincing bluegrass licks there without a capo.
So I use a capo as a tool, not a crutch; just like transpose.

As a sax player mo, would you be thrilled if your sax had a transpose button? Would you have as much respect for (insert your favorite horn player) if you knew he only played in C? Since you're not a piano player, you do what you have to do to sound good; but it shouldn't be that hard to understand why actual pianists might have a gripe. There's something to be said for the authenticity of style and variation that happens when an instrument is played in the actual key; and if you don't care about that, then you don't, but some of us do. You're going to do some things playing in C that wouldn't be done in Ab; and that bugs some people. If you were listening to 1:00 jump (in Eb for tenor), and suddenly a tenor sax started taking a solo; but it just wasn't right somehow. It sounded like he was playing in C. So the octave key and its associated timbre and color were happening on the wrong notes. You would have no tendency to thumb your nose at that? You wouldn't be bugged? I would. The reason it doesn't bug me in bluegrass and such is because that precedent was set when that style of music was invented, so it has always been part of the sound of that music.

[This message has been edited by FAEbGBD (edited 06-02-2010).]