In the quest for economical use of scarce resources (which caused the Y2K problem, but that's another story) I have been experimenting with Portable Apps.
This is a wonderful trick; a bunch of open source applications have somehow been reduced in size so they will fit into about 320MB, installed on a 512MB SD Card in the Eee's card reader slot. The applications include Open Office 2.4, the Mozilla Firefox/Thunderbird/Sunbird combo, and lots of others.
I have trimmed my selection a lot, as I already have Firefox and Open Office 3 installed on the D drive, but I'll probably add GIMP for photo processing. At present I'm using only 102MB, leaving 380MB on the card for saved files.
How do they do this magic? The explanation for beginners has some information, but I don't think I'm enough of a codefangler to venture into this side of things. I'm happy just being a user.