I like the idea ‘zero time installation’, or ‘on demand available’. One way (the big one) is to make virtual machine and with VMWare player just run it or what you got preinstalled and configured – this work fine for complex software, where installation and configuration maight take vast amouont of time. However the second way for small applications (‘tools’ or desktop applications) it is enough to have them just on portable media and run it directly from it. flash disks has great potential as a ‘HW platfrom’ for running these apps. I recently come to blog of James Fee about portable GIS experiemnt with QGIS. I tried it (just copied extracted files from dwonload site to flash disk) and it just work – running out of my flash disk driver. There is bunch of portable applications on portableapps too, mostly for office apps, browser, file managers, etc. And I am sure most well writen applications/tools can run directly from flash disks, just they don’t think it is a ‘great feature’ to list it in specs, but it is !