[PA_Willy]

I have used nHancer in the past, but i can't say that it made any difference to my coastlines...

Of course. Only using nHancer you aren't going to see any difference. You have to switch to SSAA (enabling one of the supersampling modes).

This is a very old issue. There are hundreds of threads in SimHQ, UBI, etc. If you don't know about what issue we are talking, better for you.