NFS home folders, as suggested in the comments, clearly are a good answer. But, NFS can be a pain if your network setup is not 'static enough', for example when working with laptops etc. As the directory is accessed remotely (as supposed to 'synchronized', as in windows domains), it means that you have no access to your home directory when a network outage happens.
Samba/CIFS (see http://www.samba.org/) provides easy shared folders, and is quite tolerant to network outages. Again, files are accessed remotely, and are not available when not connected.
I personally use unison
to synchronize my stuff between machines. One might argue that DropBox
provides the requested functionality, if you are ready to have your data in the cloud. Ubuntu specifically has the Ubuntu One
, https://one.ubuntu.com/, which does a similar thing.