Once upon a time, in a DOS-galaxy far far away, applications were portable, fit on a single "piece" of removable media, and didn't take the good chunk of an hour to install while they thrashed away at updating registry entries, typically rebooting to reload the new settings before they were "finally" installed.
In an ideal world, I'd be able to jack in a USB key with my favorite applications into my laptop, or someone else's desktop or laptop, and be able to work as I pleased with the tools I wanted. A partial solution has been rolled out with the U3 platform (www.u3.com), so if you don't mind working in a non-Office environment, you can have everything from Open Office's suite of biz tools to a mobile version of Skype.
Can you cram your whole desktop and relevant data into a 2 GB USB key? For simple word processing, it's no problem, but if you want to "go mobile" with all of your stored documents and e-mail, you have to have the storage capacity of a bigger hard disk. For various reasons, I've been keeping an archive of e-mail for the past several years and it's at 2 GB alone - not exactly something you can tuck away on a USB key on a cost-effective basis. Throw in Google Desktop Search so you can sift through the messages and add indexing to get a real mess.
A better answer would be to enable a limited form of file mirroring between desktop and laptop, either by direct connection via Ethernet or (my favorite) via a yet-to-be built hard drive/laptop combination where the disk drive can be snapped out of the laptop and slid into a docking station on a desktop for file exchange/updating OR backup. Press one button for mirroring/data sharing, press a different button for backups before you go to bed, wake up in the morning and everything is nice and tidy.
Another annoyance with current software is that it always wants to be updated at the most inopportune times. If you are traveling on the road and sitting at the local Wi-Fi hotspot, you get offered the "opportunity" for updates for Windows XP, Adobe Acrobat, Real Networks, the anti-virus program du jour, and whatever else feels it is 30 minutes out of date. Every software company uses a different system to poll for and deliver updates. There's no centralized "panel" within XP or made by a third-party that allows you to intelligently "shut off" software updates when you're away from home.
Instead, you have to say "yes" or "no" to each and every vendor, typically on boot up or when the application is first run because the very first thing it does is hit the InterWeb to see if it's got an update back at the mothership.
I'm not sure if the chaos of automatic updates will be solved short of a set of non-Microsoft vendors sitting around at a table and agreeing upon a standardized way to handle update requests, something that's not really likely to happen because every software vendor uses their own method to deliver updated code. ยต