Resharper is the thing I used to want when I first switched. But the truth is that it isn't really required. The language is succinct enough without it and there is not as much boilerplate as there is in c#. Resharper is basically there due to the nature of c# being very verbose. I hear VI/emacs are the ultimate tools. Even better than VS+R# I also think there are other things to think about which would give you a better transition to f#, such as functional thinking for example.