I've got my Eclipse 3.4 envirnoment set up nice and cozy the way I like it. Took me some time too, to find all the plugins (Mylin, PDT, Subclipse), set all the settings, etc. Now I see that some of the plugins (like PDT) only support 3.5 in their latest versions.
Is it possible to update from 3.4 to 3.5? I'd hate to do it all again.
I read in some mailing list where they noted that it's possible, but the conversation trailed off in another direction. Google wasn't much help, and Eclipse's documentation either.
All of your settings are actually stored as part of your workspace. So you could do a fresh install of the latest version of Eclipse, add the extra plugins that you want (many of which will have newer versions for Eclipse 3.5) and when you launch, just make sure you point to your old workspace.