Sundance,
Of the three pistols you mentioned, I would probably go with the Colt 1991A1. It will give you the opportunity to ring out a design completely different from your Glock. If you decide you don't like it, the Colt will probably hold it's resale value somewhat better than most other brands. Now, having said that, don't put too much stock in any particular brand as far a quality is concerned. Buy the brand that feels best in your hand. As long as you stay with a major manufacturer such as Colt, Kimber, Springfield, etc., you'll be fine. They are all about equal. All make fine pistols, all spew forth an occasional clunker, and they all come with a factory warranty, although you probably won't need it.hth-TR