61SL MKIII : This is the ultimate midi controller

For whatever your purpose, the SL MKIII has you covered. I primarily have used it to control soft synths and piano plugins, and for those of you wary about semi-weighted keys, these feel really good. They aren't as hollow or as plastic feeling as the ones on the FL key and they hold up to a fatar keybed, albeit not the exact same feel. Highly recommended for home studio recording and for live performance. The interface is very intuitive and you can have all of your controls mapped in mintues. A number of plugins and hardware synths are supported and already mapped, and the SL MKIII can control multiple devices at one go. It's such a powerhouse! Fairly priced, and definitely worth the money.