The other were horrendous insults to good url design (even Stackoverflow's). The only one that was reasonable was 37sigs. I didn't really give it any thought, ours would only have been like 2 chars shorter. Or perhaps it was self-promotional instinct :)

You can also shorten the StackOverflow one:

http://careers.stackoverflow.com/jobs/10660

Also a note, HN automatically truncates overly-long URLs so you don't usually need to worry about pre-shortening.