Druids are my favourite solo class. They can do everything, and this was before their first talent review.

5x Warlock (levelled affliction towards SL/SL) - Insanely fun due to the pure overpowered nature of the group. Once you get instant corruption it just gets better and better. You no longer put up a 'dot' on a mob, you put up an ellipsis. Fear is no longer used for CC, its used to aggro more groups. So many laser beams you can almost smell the melted faces. Your own personal zergling rush without having to build a spawning pool (fel puppies remind me of zerglings). Extra fun on a PvP server for ganking skulls.

1x Priest (levelled deep holy) + 4x Warlock (levelled deep affliction) - Just as fun to level as above. Once you get CoH bind it with life tap and roll your face on the keyboard.

5x Shammies - Slow to start off and feels very slow after having done warlocks. Just feels like im playing 1 toon that hits harder.