that is a nice laptop. i don't know how xp comes into play, but i mostly see folks with win2k as the operating system of choice. of course a dual-boot is possible, too.
the vx pocket is nice but SINCE you have firewire, i'd look into that option because you can interface much higher sampling rate if your a>d has that potential (ad2k or something like it). i think edirol makes a firewire or someone else, and it seems like you may actually be able to notice a huge difference in sound, as opposed to 24/48.
batteryspace.com has your battery needs covered or you can get a valence n-charge pack. good luck.