Hey, what's your favourite foot to walk on? Or your favourite gear for driving in? ;-)If I'm playing around, it'll usually be in key of A, Am, Bm, C, D, Dm, E, Em, F or G - they're all handy for playing stuff in. No real preferences. Although a G chord in drop-D or double-drop-D sounds sweet.
Almost always though, I play capo-2 or capo-4 to suit my voice.
Graham.