I've always been confused about the so-called "bugginess" of Derelict - I never ever had any problems with it.
I'd have to say (in no particular order):
Derelict (dream sequence and chasing/running away from the Auriga - great stuff)
Warzone (groovy Explorer ship, some rather fun missions)
The Aeos Affair (this is awesome, short, but hard as hell, and great fun!)
Homesick (though I never actually finished it, 'cos the machine it was on died half-way through. I'll definitely play it again, though)
Into The Night: Exposition (158th campaign) (very hard, cool mods, I helped make it

)