A retirement gift to yourself I assume?
If it were me, I would go for the .357 without hesitation, but that's me, and I always go bigger.
But seriously, from a practical stand point, the .357 would be nearly impossible to wear out if all you plan to shoot is .38's, even if you shoot super potent loads. Carbon rings are so easy to remove, that I wouldn't even give that a second thought. Wrap some 0000 steel wool around a bore brush, a dip in solvent, and carbon be gone. I shoot a good deal of potent 38's through my .357's and they do develop some serious carbon deposits, but like I said above, they clean up in just a few short minutes. And if you do decide to just down load .357's, at least you'll have the option on the table with a .357, and as well the option to shoot full house loads if you ever feel the need.
As for which brand / model, I would probably go with a Ruger or S&W something, that part you'll have to decide by how it feels in your hands. But if it were me, I almost certainly go S&W, they're so clean and smooth, IMO. Whether you prefer DA or SA, snub or longer barrel, those are all things you'll need to decide for your self. Maybe rent / shoot a few, then decide based on how they handle for you?
GS