I like the 2D and 3D Metroids about equally. I don't know if I've ever had a gaming rush like the time I beat Super Metroid, though. Maybe in a few particularly intense battles of Smash Bros.
The scavenger hunts didn't bother me, because I'm a very thorough person when I play a game so I had most of them by the time I had to collect them (in Wind Waker and Metroid). However, I do consider it a design flaw, and wish to this day that they'd delayed Wind Waker to add the extra dungeons and stuff.