Personally, The BH has the coolest ship of the bunch primarily because it looks like a completely awesome cross between the Slave I and Serenity (from Firefly). My least favorite it the Trooper's since I find it kinda ugly IMO, probably because I prefer the more symmetrical designs.
All told, my list goes like this:
Mantis>Phantom>XS Freighter>Fury>Defender>Thunderclap