I'm on SugarSync - their app is pretty decent and because you can choose what folders on each computer to backup, you can browse through each of your computers documents.
Actually Microsoft's Skydrive is great and so is Dropbox. Box.net is great too.
Yeah I saw one could get 7 gb free with Microsoft Skydrive.
Cool. By just registering?
Dropbox.
It is great my whole company uses it and it works cross platform so it does not matter if you are on Windows, Mac, iPhone, Android or Windows phone.
I am hesitant when it comes to Dropbox and work. Recently a bunch of my colleagues who used dropbox had a virus.
I've been using Dropbox myself with no problems but it made me realise that maybe a few alternatives might be a good idea.