I'm curremtly using BIAB on a desktop computer. Running 2012 Everything Pak on Windows XP pro. bit. I also play keys and am thinking about going to a more mobile rig. I know there are many choices for laptops-- over the counter VS pro build as well as pro audio/midi interfaces. My concern presently is what would be a better unit(laptop vs rack 3U space)
I would like a mobile computer for the following:
1. use BIAB and Sonar Home studio and eventually something Like Ivory or other key based software for live performance. Presently using hardware. (Yamaha S90, Kawai MP4, Korg CX3, Gem Piano module and Ketron SD2)
2. Be able to record band sessions (practice). Multiple locations
3. Able to take keyboard to cottage/vacation using software listed above.
4. Low latency for live use
So before I get into what processor,how much ram,what interface,and so on, I'm seeking advice from folks who might be in a similar situation. Laptop VS rackmount

Obviously the laptop is the most portable which is definately what I'm after. Looks like on todays laptops USB is pretty much it. Firewire seems to be going south and the usb2/3 inputs would be limited. Never had a laptop so I'm concerned with how long these PC's last

The 3U rackmount would be another consideration. Still not too heavy to lug around and more choices as far as # of ports, interfaces, etc. Though, still have to factor in a monitor, keyboard and mouse.
Any sugestions from those who use laptops or rack mounts especially for live performance.