I always get bummed out when people hate on the Enchanted Tiki Room. I love it! It's one of the first attractions I really remember seeing ('73 or '74), so there's the nostalgia factor. It's such a classic Disney attraction and it doesn't get the love it deserves.
My other "relaxing ride" is the Haunted Mansion. You know Disney did something really right when people still love an attraction that's over 40 years old. It's the ONE ride at WDW that I must experience every time I'm there. Nothing else is close.