I used pico and pine sometime back but dont use it now... both of these UW software are non-free software...
I use mutt and emacs .... I've binded emacs with mutt so all the mail composing is done by emacs. MUTT is as featureful (actually more !!!) as pine.
ps: many people love PICO, so there's also a pico clone called nano , its a free software and all the key bindings of pico are same and its interface and key shortcuts are almost the same...