F# does pretty much everything C#, only easier. It's advanced features mean you end up writing a lot less code. OO syntax is more verbose than the other F# syntax, but it's still better than using C#.
We're using it for web services, ASP.NET MVC sites, daemons,
The question is, where not to use it. Right now that looks to be mainly where tool support is lacking. So, for example, with ASP.NET, the ASPX page inline code is C#, but the controllers and everything else is in F#.
The few places where F# isn't as smooth as it should be I imagine will be worked out in the upcoming releases.
