Spaceship Sizes

An interesting URL : Jeff Russel's Starship Dimensions. How big is the Death Star? Or rather Death Stars, v1 and v2 are of different sizes. And how big is an Imperial Star Destroyer compared to the old original NCC-1701 USS Enterprise? Which is bigger, Babylon 5 or the Vorlon Planet Killer?
Here's the Vorlon:

And here's B5 to the same scale:

I had no idea.