The Gorillaz made a new album using an iPad:
Listen to it here.
Here’s the iPad applications used:
Speak It! / SoundyThingie / Mugician / Solo Synth / Synth / Funk Box / Gliss / AmpliTube / Xenon / iElectribe / BS-16i / M3000 HD / Cleartune / iOrgel HD / Olsynth / StudioMiniXI / BassLine / Harmonizer / Dub Siren Pro / Moog Filatron