Okay, I'll play. One ship per franchise off the top of my head, without images, because I'm lazy. Also note that I'm distinguishing "beautiful" as being "aesthetically appealing" (so that pretty much rules out anything from 40K for instance)
-Glorious Heritage-class cruiser (Andromeda)
-Mercury-class Battlestar (Battlestar Galactica)
-Moya (Farscape)
-Firefly-class transport (Firefly)
-CSO-class supercarrier (Halo)
-ISA cruiser (Killzone)
-SSV Normandy SR-1 (Mass Effect)
-Blue Typhoon (Sonic the Hedgehog)
-USS Discovery One (Space Odyssey)
-Spear of Adun (StarCraft)
-Great Fox I (Star Fox, as depicted in Star Fox 64)
-Daedalus-class warship (Stargate)
-The Constitution-class or Sovereign-class (Star Trek, can't decide)
-Imperial II-class Star Destroyer (Star Wars)
-TARDIS (Doctor Who...shadup, it totally counts)
-Bengal-class carrier (Wing Commander)
-Heliades-class space exploration vehicle (Xenopedia)
-Hermes (The Martian)