I used to be a fan of the Clockworksynergy bands, but sent one of their more recent NATO band purchases back - it was paper thin, not the quality I was used to. Heh. I likely have about 30 bands (and before you make that face - there used to be clones of the Apple sport band on Amazon before Apple got them to take those storefronts down - I scored about a dozen of those.
(they were about $10 each?)
Originally a S0 (space black with the link band), then the S3 - likely upgrading to the S7 this fall. (the S3 is starting to show its age with WatchOS 8)
IMHO, the killer apps are Siri (while peering into the fridge "Hey Siri, add onions to my grocery list"), timer, having it sideways on a charging stand so you get alarm clock mode, of course the exercise app (filling your rings is addictive)
Turn by turn directions (with the taps on the wrist) is pretty nice in sketchy neighbourhoods.
. (or as another reminder when you're driving)
Edit: Oh..and if you want to leave your phone at home, there's a reminders app for WatchOS, useful for your groceries list.
Edit: One more - with the Find My app in WatchOS 8, if you DO leave your phone at home and didn't mean to, it tells you!
. (provided you don't disable it) - this saved me the other day - got the notification just walking out of the lobby of my building.
(Apple Maps still seems to only be doing 2D btw - hopefully they start doing more with elevation).