I LOVE the third generation S&W semi-automatic pistols, especially the full-size models with the 5" barrels.
I wish that S&W would put back into production the .45 ACP full-size pistols (4506 and 4505).
I also wish for the return of the 5906. That double-stack model just "fit" my hand perfectly. (You know that feeling, the first time you pick up a new handgun and you just know this one was built just for my hand?) The 4" models are available used, though most saw a pretty hard life as police duty weapons. The one I liked best was the Super9, with a 5" barrel. That one is available used, but is crazy money, since it is so rare. The 5" barrel seems to balance and look the best IMHO.