I'd have to go with KLAS as well.
1. It's home. Not often that with McCarran being so detailed (bloody hell, you can follow the tram down to the tunnel for the D gates! Or better yet, drop off people (by plane, obviously!
) at the ticket check-in, or tour Signature), but combined with the LAS2004 scenery, the aforementioned downtown LAS scenery and BlueSkyScenery's LAS HiRes and Low-Res sceneries, when you get a very accurate depiction of the entire Las Vegas valley. Besides.. It says a lot when you can pick out exactly where you live in the scenery you're using.
2. Performance. ~40-55fps with traffic using an eVGA NVidia GTX460. I was getting similar (~30-40fps) with my 8800GT, though I did lock that to 60fps. No stuttering whatsoever.
3. Finally, a decent scenery to run LAS in Configuration #6. Can you say 'Right Traffic visual approach runway 19L'? In short, fly in from the west or from the south, roughly 10DME west of the field (puts you over Redrock Canyon). Abeam the Stratosphere tower, fly your base leg to the 19s. Turn to final, and you're done. This is one of the traffic patterns they use in the summer, when they land and depart to the east and south. What makes this fun is that there are rides at the top of the tower (roller coaster, ride that hangs off the tower, death drop on the needle, and most recently, a 50 - 100ft drop off the tower). So to see a Gulfstream, Falcon, B737, etc, coming at the tower while you're on the ride is a rush.
BL.