I tried Dropbox when I was doing my first MSc module.
As the course involved writing code and documents, I would work during the day when I was onsite on my laptop, then switch to my desktop to continue working for the week.
Naturally, I would forget to copy something to my laptop ready for the following week, so I tried Google Docs and blogged about it here. Pretty good – just a little clunky and not quite up to the job with the maths symbolic stuff I needed to use.
In a comment to that post, Luke Maciak suggested Dropbox. (Incidentally, I can recommend his blog for entertaining reading too)
Using it, I get an online repository where I can put files, and I can download client software for my (Windows when I was running Windows) and Linux machines.
The client software gives me a ‘Dropbox’ folder. Placing any files in there synchronizes them with the online repository. Any files I’ve added or updated on other machines are synchronized down from the repository, and I can get to and share my files via the Dropbox website as well.
The main difference for me is that Dropbox is completely transparent. It’s just files in that folder. No messing.
So far*, it just works – in fact, I’ve started using to to share some of my Ubuntu desktop configuration. Everything behaves exactly as I expect it to, and there’s been no nasty surprises, so I’d tentatively recommend it if you have multiple computers that you want to keep files in sync across.
You get the first 2GB of space free. If you’re interested in giving it a go, you can get Dropbox here.
*of course, tomorrow it will probably break. That’s computers for you. I’d suggest taking your own, separate backups of that ol’ Dropbox folder now and again, just in case.
crossedstreams.com 
How has been your experience using DropBox on your HTC Magic? I’ve got a MyTouch 3G (what we call the Magic in the US), and I think it’d be great if DropBox had a client for Android.
Hi A.Y. Siu.
To be honest, I’ve not yet had a reason to try and access the documents in my Dropbox account from my phone – so nice question!
There isn’t a Dropbox client for Android, and no API though which a developer could write their own.
Personally, I don’t think I’d use a Dropbox client to be honest, I don’t think I would like up to 2GB of files being kept in sync with my mobile phone, and I can’t imagine I would want to do any editing on the phone. Are you thinking photos, or do you have other uses in mind?
I figured that the web-based access would be enough. Going to the site and downloading a few files shows a couple of things.
1) It works.
2) On the downside, files without a specific type (which seems to be based on file suffix, .txt, .pdf etc) can’t be downloaded on the phone, as Dropbox tells the phone they are binary content and the phone doesn’t know how to open them.
3) You need to have appropriate helper applications installed on the phone to be able to open files you download from Dropbox, including PDF and Office files. There are free apps you can get off the Market that work pretty well.