Reflecting on the 'bedroom knob' thread from yesterday re Drum Machines, what is the iPad music app you get the most use out of / sounds the best / most creative, etc?

After buying an iPad Mini a few months back I thought I'd be using it for Internet malarkey, games, iTunes, etc but I'm using it more and more for attempted music making. I've got Tabletop, that AKAI app (which works in Tabletop too). Figure (creative and cheap). Any more I'm missing out on?