Welcome aboard.

Scenery add-ons: There are freeware scenery add-ons for just about anywhere you care to mention along with the payware stuff. It's really a matter of personal preference in terms of where you like to fly.
Personally, I have about everything freeware going for the U.K. and Gary Summon's payware UK2000 airports series and Simflyers Manchester Airport as payware.
Other than that, I tend to install stuff for places where I've been (Changi in Singapore being an example). I can't ever recall adding scenery that wasn't an improvement on the default, so you really can't go wrong apart from with frame rates. Some of the really detailed stuff will hit your C.P.U. hard.
I fly around the world at the moment to keep it interesting for me. The link in my signature is the site where I report on the flight and post screenshots. Again, it's ll a matter of what floats your boat.

Favourite area so far for VFR is Nuuk in Greenland - spectacular
