I never commit those (esp .project) and always vote for them to be svn:ignore'd. Maybe I'm wrong but I only commit code to SVN and then make a new project by checking out from SVN.
Every time I checked out a project which had those files commited literally BROKE my project. But then again maybe thats just my coworkers...
By breaking i mean converting these
src/com.package.name1
src/com.package.name2
src/com.pack.name1
src/com.pack.name2
to these
src/
src/com
src/com/package
src/com/package/name1
src/com/package/name2
src/pack
src/pack/name1
src/pack/name2
and other sorts of unnecessary irritations... like them not being recognized as packages anymore but as folders. One of those things that makes you have to run eclipse -clean or delete/reimport a project or waste time on eclipse stuff you don't wanna waste time on.