Just cured a frustrating problem: If you use subclipse and subversion > 1.4.5 then Eclipse will crash often as soon as you start up. This is to do with an incompatibility.
See the entry entitled "As soon as I do something with Subclipse on Windows, Eclipse just crashes. Why does this happen?" at http://subclipse.tigris.org/faq.html
Just thought I'd post here in case someone else was having this problem.