I found it tedious to reinstall all the plugin every time upgrade the eclipse.
This is the best option I've found so far. Dropins directories work, but they're a pain to maintain, because Eclipse wants to install new plug-ins in the Eclipse directory.
I. To transfer your list of update sites:
Window->Preferences->Install/Update->Available Software SitesExport, save the file somewhereWindow->Preferences->Install/Update->Available Software SitesImport, choose the file from step 3II. To copy across your old plug-ins:
File->Import->Install->From Existing Installation~/apps/eclipse-jee-indigo-SR1-linux-gtk-x86_64/eclipse/Finish