X-plane is the one..
I have to agree on this, x-plane version 9 is without doubt the best sim you can lay your hands on for the pc (version 9 is current). Most folks I know use it for IR training and this seems to work very well for them. You need a decent set of controls though (Saitek throttle/yoke thingy and pedals) and a decent processor and graphics card.
For sweaty hands realism, run it through a Matrox triple head adapter over three screens and a track IR 4 for looking around the cockpit and you have one very good sim.