Given just the info you have provided, taking in to account what you say for condition and showing the prices you listed, I think it is easy to pick a winner:

The 3914NL at $475 and in California at that is clearly the best buy if what you seek is VALUE and/or possible collector "future value."

I'm confident in that, and that all of the others listed take a back seat. The only one that comes close is a 5904 at $400.

The 39-2 is the one from the list that I'd most want to own but at $600 with only medium condition, I'd pass simply because there are tons of 39-2's to chase. Yes, "California" skews that a bit, but I'll hold dead firm in my assessment of your list.

There are two listed that are, IMO, lousy deals--
That's the 910s and 915. The 915 is a great gun but they made a zillion and that means $450 is too much unless it is NIB with full box. The 910s is a full value line and it is an inferior gun to EVERYTHING listed, and that price is lame out here in free America. It might be a solid price in California, but in the list you show, it's the "face down in the gutter" failure of the lot.

Hope that last line didn't offend anyone too much... but the 910 must be one of my least favorite S&W pistols of all time.