ndmvhc: Well, the original Russian censors cut it. Garnett's translation from sometime in the 1910's included it as an appendix. Pretty much every translation since then has restored it to its place (and it is central, more or less the equivalent of "The Legend of the Grand Inquisitor" in Karamazov.) I would tend to think any modern edition that made a big deal of including it is probably trying pretty hard to flag down some business. (That said, the MacAndrew translation might be utterly awesome, I wouldn't know.)
Hey Dave: IMO, yeah, If you're going to read only one of the Dostoevski Big Four, Crime and Punishment is the one. Fairly reasonable length. Relatively speaking, more or less a page turner. Covers most of the big themes with a relative minimum of extraneous fustian. Get the Pevear/Volokhonsky and absorb it contemplatively over a samovar of tea and some big ass, skunky brown-and-black cigarettes.