The legendary Into the Lion's Den, with the no-less legendary DIVE DIVE DIVE

just the best mission ever, you really feel like being deep behind enemy lines. Also, all those new Sathani and another Knossos, this can really creep you out.
Bearbaiting - you have lots of enenmy fighters on your tail, flak is everywhere, and you try to desperately get a lock on one of those huge-ass BFReds. Along with the music, you feel like it's "OMFG, the end of the world !!!"
As the Lightning Falls - if not for those crappy waypoints, which spoil the fun, the EMP storm is really creating a nice atmosphere. And it's the first time you're given the Erinyes and Kaysers + Tempests - pure pwnage.
Also, the whole Transcend - geeez, now those missions kicked ass. The best FS2 campaign ever made, IMO. Each and every mission is a masterpiece. It's a must play !