I found myself recently copying firefox and filezilla to my stick only to find they were already there and I had just forgotten to make use of them.
There are basic sets of programs we would all choose to have available wherever we go, and until we are all "cloud" users I reckon the memory stick is the way to go.
I found this was linked from a blog when I was catching up on my feeds tonight and thought I would make this post and share it.