Ive just purchased Railworks 2 as that appears to be the sim of choice on the net. I have Microsoft train simulator and that was good in its day, but on today's equipment looks a bit outdated. Am looking forward to Railworks, its on back order so Ive got to wait for stock but as soon as it comes Ill let you know how it is. If anybody has any input, do's and don'ts it would be handy.
As for Flight Simulator X, its a great game. That said, I personally wouldn't purchase it now with the new Microsoft Flight on the horizon. For a game that was released a few years ago you would think that the kit of today would be able to max it out, but it can't. The scenery, although an improvement on previous Flight Sim versions, still isn't a match for some of the custom scenery on the market. This to me is annoying when you pay a considerable amount for a game.