Deadmau5 has worked with Skrillex, Jason Derulo, Travie McCoy, Gerard Way, who was featured on a song from Deadmau5's latest album, and many others.
He has collaborated with many artists tracks, and done remixes of songs such as Rage Against the Machine's "Killing in The Name".
Deadmau5 has a large rig of equipment and software:
Nord Lead x2
Moog Little Phatty
Voyager RME
Ableton
Fruity Loops
Allen and Heath Xone 3D
Allen and Heath Xone 4D
Lemur Input Device
Ableton Live
Monome 256
Reaktor
Cubase
Kaossilator
Nuendo
Native Instruments Maschine
Smithson Martin Emulator
Dave Smith Instruments Prophet '08
Here are also some pictures of Deadmau5 live, and some videos of his performances.
Below is a video where he speaks of using Ableton and other things in throughout his rig.
Above is a video of Deadmau5 talking about his gear.