Flash drives are carried around by millions of people every day because of the convenience that portable storage offers. You can use your flash drive for so much more than carrying documents and a few sites, like PortableApps.com and PortableFreeware.com, make it easy for PC users to take their favorite applications wherever they go.
FreeSMUG (Free OpenSource Software Mac User Group) offers the most popular applications, and some not so popular, for the Mac operating system. You’ll find everything from Firefox to Thunderbird all the way to Gimp and OpenOffice. There are several different types of applications including a few different feed readers so that you can keep on top of the news from any computer. They even have Mac-specific software like Safari!
While I’m not a Mac user I do use a lot of portable software on my flash drive. I do have some encounters with Mac’s every now and again so I think I might throw Firefox on my drive just in case.