I've got a 4" S&W 686 -- one of the original square butt ones, no dash. For home defense, you would be hard pressed to get any better than that in a revolver. Or anything else, for that matter.
Personally, if I were to be buying right now to fill the niche that your friend is looking to fill, I'd be considering the following:
USED: Any S&W K Frame .38 Spl or .357 Mag or L Frame .357 Mag with a 3" or 4" barrel if it is in decent working condition. Look for those that are pre-lock. Also consider the medium frame Rugers, such as the GP-100s and the Security Sixes in the same barrel lengths. Don't be afraid to look for Law Enforcement trade-ins, there's some good deals to be had there.
Colts are nice, but are pricey. If your friend wants to pay the price, they are decent guns.
Used Taurus's are out there, but in the used market you can get LE trade in S&Ws for similar prices so why bother?
NEW: Right now, if it were me and I were to limit myself to just the new gun market, my list is really short. In my mind the field is down to 1 -- Ruger GP-100. I'm not really sold on the reliability of the Taurus revolvers, gun to gun -- yes, some are good but I'm still not convinced that they are ALL consistently good. That makes me uneasy about recommending them as a first, and perhaps only, HD gun (Their PT-92 is another matter, but that is an autoloader). S&W has alienated me, and IMHO has taken the wrong direction in their manufacturing processing as well as their PR efforts. So, as much as I like the guns that they made in the past, I'm not buying any new ones from them.