I've had Microsoft Source Analysis (AKA StyleCop) installed for a couple of weeks. Yesterday I have very belatedly taken the plunge into Resharper.
I have gotten used to the style promoted by Source Analysis. I've gotten into the zone of feeling that warm fuzzy glow from code having no warnings. Howard van Rooijen calls this something akin to OCD and he may be right.
As an aside, if you're coding in C#, I feel that you should get used to the coding style that this tool promotes. It's the most authoritative standard layout that there is, and will most likely be widely used. It's the style that has the backing of Microsoft, and has tools for checking adherence. Other styles don't have those advantages.
All I've done with it so far with Resharper is similar OCD-type things, clicking on what it flags up and deciding to suppress or fix the message for a similar warm-fuzzy feeling when the code is clean again.
There were reasons why I didn't install Resharper sooner - resharper 4.0 has just recently come out of beta, and now we have licences on request. So far, Resharper has been excellent and you should try it at your convenience.
Unfortunately, the two tools don't play well together on all machines, and my laptop is affected. When I edit project properties I now get an obscure error: "COM object that has been separated from its underlying RCW cannot be used."
This error is mentioned here and here.
I now have to say goodbye to one of these tools until this situation is resolved. From this laptop, Source Analysis has gone on holiday. Hopefully it will come back soon, feeling refreshed and ready to help me out. Resharper and I are waiting.