The local shops have started selling the Phoenix RC flight sim so I picked it up.. I'm pretty addicted to it..
I don't know how realistic it is but it's definitely a lot of fun..
It has a lot of models that you are likely to fly or already own.. It has incredible graphics with 3d landscapes and flying sites.. And you can fly online with other people and you get to watch them fly..
Horizon is the distributor so you have the option of getting it with a DX5e or on it's own.. 3D can be flown with just a 4 channel radio and a keyboard..
http://www.phoenix-sim.com