In reply to Otis:
When I first started climbing in '72, I had heard that people led on 300 foot double ropes. Supposedly, the advantage was with no knot in the middle there was no problem pulling down your rope after abseiling. They had to tie in the middle somehow. Over time, the 300 foot ropes fell into disfavor.... Guess they were too hard to coil. But, I can't believe that the knowledge of how those folks tied into the middle was lost.
Anyway, after a lot of research, I started tying with the bowline on a bight. Didn't like stepping through the loop, though. Some claim escaping the belay is a problem but I didn't see escaping the belay as a major problem since tying in the middle of a 60m rope was for a short pitch anyways.
After a while, I switched to a normal bowline tied with the loop and just clipped the end of the loop back to my harness. Not very satisfactory, either.
Now I just use a rethreaded overhand or an overhand with a half fisherman's finish (tie an overhand in the bight, thread your harness with the bight, insert the bight through the overhand, tie a half fisherman's around the standing part of the rope)