What Moon Lancer said (and how Moon Lancer said it)...I want my nature-powered druid, and I want him now.
Power sources I would like to see:
Psionic (or ki, or mental, same difference)
Gaia (or nature, or life, whatever)
Alchemy (or science, or artificer, or spark, or somesuch)
Song (or music, or harmony, or suchlike)
And just in case this turns into a humor thread, I would like to nominate Coffee (or java, or espresso, or cuppa-joe, etc.) as a power source. Because, well...it's what powers ME most of the time.
EDIT: "Passion" is a great name for the bard's power. Well done, Mercule.