With any luck after this topic grows in size, it will help kill some of the "what midi controller should I use?" topics. (assuming it grows enough to warrant pin'd status" But for that to be possible, people need to contribute! Post the name and some info about the piece of equipment you recommend.
So here we go.
Midi Controllers.

M-Audio Oxygen 8 ~£100
For laying down synths and basslines. Find it easier than drawing in with the mouse ~ Wub
note: some members have mentioned issues when using this controller with Reason.

M-Audio Oxygen 49 ~£120
Works perfectly with whatever the fuck i want. ~Vonboyage

Novation X-Station 25 ~£250
A MIDI keyboard (there are 25 or 49 key ones), with a built in soundcard, as well as a built in Novation synth (basically a V-Station), which you can jam with, over the top of the sound that's coming out through the PC/lappy. It's also got some effects that you can apply to the incoming signals before you send them to the computer. ~setspeed

Korg PadKontrol ~£100
For laying down drum tracks and all that. Got it setup to cycle through my different Battery kits using the big silver knob, plus the touch pad bottom right controls filters and effects and stuff. ~Wub
To be continued.