A bit late on this, but in case you still want suggestions, I'd definitely go with Gargoyles Season 2: Vol. 1. Yes, it's a bit annoying not knowing if the second half will ever be released, but the first half is just too good to miss. "City of Stone" remains as one of my favorite story arcs from thie show, and "The Mirror" is considered to be the best stand-alone episode by many fans, including myself. I believe the set cuts off right after the first few Avalon/World Tour episodes, so you still sort of get a sense of completeness since season 2 basically breaks down to Avalon and non-Avalon.
As for the other things you mentioned, I did buy the first volumes of DuckTales and Chip & Dale. To be honest, I haven't watched either too much since I got them, not only because I haven't had the time to, but also because they didn't hold my interest as much as I would have liked. The TMS-animated episodes from both series do have gorgeous animation, and there are a couple of gems that I really enjoyed (particularly the Soda Cult episode from C&D), but again, some of the plots weren't interesting as I remembered. I've only gotten the first volumes of both, however, and perhaps the second volumes are better.
I haven't been able to get Tailspin or Darkwing Duck, but I think the latter is a must have. I watched a few clips on Youtube and Darkwing is still as great as I remember. I love a good superhero parody.
I also picked up the first volume of Dinosaurs a while back and enjoyed it. The video is a little strange, however, with a certain blurriness to it. I think it's because of the way they shot it, though, and not because of any transfer issues. Otherwise, the set is great, with plenty of features and dinosaur/easter eggs.
As for DuckTales: Treasure of the Lost Lamp itself, I've read that the Movie Club version is indeed widescreen, so I wouldn't worry much about the transfer. The rumor is that it will eventually get a wide release, since it was labeled a "Disney Movie Club Premiere" and not as an exclusive.