3.89 or higher... With any reasonable horsepower, a 3.89 will be plenty low and make first gear a trick to keep hooked up.

For a vehicle that's going to see mostly street cruising I would opt for a 3.70 or less.

For me I switched from 3.73 to 4.10 and it made the car a lot easier to drive on the street. Agree that first gear is a little short now, but with 3.73's, sixth gear was useless unless I was going faster than 75 mph and was on a flat road.

I have the T-56 with 2.66 first gear and a 383 SBC with a aggressive cam, so I personally needed the higher rpm.

For what it's worth, I have the motive gears (4.11) out of my DSE rearend that they built. I went to a 3.50 for turbo car as mentioned before. I'd make someone a smoking deal on them :) They're "new" as they've been installed but have never had power put to them.