Breaking Mach 1 was completely awesome, so was the separation sequence and all the 'special effects' that no game or movie ever gets right.
Now, where did I put my Orbiter installation?
edit - the booster re entry part is great. Stuff just flies... everywhere! Unique that the sound is well edited on this one, at the end you hear a nice structural groan as the SRB's parachutes start to deploy.