check out
Live.
I have the axiom 61 and it's sweet. ableton also has a live pack out for it that has control mappings already programmed in 3 presets, which should save you at least a couple hours of dicking around. If you are going to want to record anything, you're going to run into latency. To record you'll have to buy an audio interface (stay away from firewire if you want to be mobile... you'll need an ac adaptor for it since you're not running mac). what kind would depend on what you're intending to record.
and reason doesn't surpass real hardware... some things just don't stand for emulation, but it is a hell of a lot easier to set up and tear down.