Kottke.org listed an old (but much beloved) nerd link, Jeff Russell’s Starship Dimensions comparison site (as well as the Sci-Starship Size Comparison site, which I think is far inferior to Russel’s site), but as with most things on the internet, deep reading returned some new (to me) goodness.
To whit, a technical discussion on the actual size and dimensions of both Death Stars, in which some intrepid souls spent a hell of a lot of time trying to figure out just how big those planet-death dealing monstrosities really were. The ‘official’ size of the Death Stars is listed as 120km and 160k in diameter (respectively), but this extended discussion points out just how off those numbers have to be, based on a variety of contradicting material.
Seriously, these kinds of discussions are as good as coffee to me, but mostly it makes me want to play X-Wing vs. Tie Fighter.