portable Apps are great peace of work with very useful and handy apps like for WebApps development. Incredible.
I've already using it along with other unported apps like Mplayer, Winamp, totalCMD,... which was quite easy to make them portable and everybody can done it itself:-)
The thing I miss is portable Virtual Desktop Manager for Windows.
There is already such great one GPL: VirtuaWin
And this one seems not so easy to make it portable and probably others could appreciate too.
Try it and you'll see why just this one.