I've been using Build 5.0.1648 of Resharper, and sometimes, after switching back and forth between applications and VS.Net, Intellisense in VS.Net 2008 on Win2003 Server just stops working. None of the triggers other than ctrl-space work at that point. I don't have any steps to reproduce this yet.
Other than that.... Resharper 5.0 has solved most of the issues that plagued me with 4.5. Nice work.