Freebie Online Disk Storage, Ubuntu/Linux... aDrive.com
I just took a quick spin, so your mileage may vary, but trying out xdrive (AOL, 5GB), skydrive (Microsoft, 5GB) and adrive (? 50GB) freebie offerings under linux (Ubuntu/Firefox 3.01) and the winner is...
adrive.com. All three of them rely on either funky java clients, adobe air (you need to run that in wine) for xdrive, or worst of all, form submission one at a time for skydrive. Unlike the other two, adrive's java client worked without any mojo here. I was able to upload a folder just by, gasp, selecting the folder. 
50GB in the sky for nothing sounds like a good deal. Privacy/tin foil hat types will want to limit this storage to "riskless" stuff like photos. I could really see the value of this for vacation photo store. Never hurts to have a copy of those digital photos backed up before heading home. Anyway, give all three a spin for yourself.
Update... some downsides to adrive
adrive has the following limitations (that I have discovered, so far) on the free version:
What's that you say? Just zip em all up and upload? Well, then limit 2 kicks in:
Which leaves dodge #3. Create zip file, broken into 2GB or smaller chunks, and upload the chunks one at a time. I'm thinking that would work, but its hardly worth doing.
I still can see the value for a quick dump in the sky store, and that 1K items/2GB per upload limit isn't all that egregious, especially for free.