I know this is not going to be a "helpful" answer, but it is an honest one...
I have only been diving in Jamaica (Negril, MoBay & Runaway Bay), Antigua (St. John) and Wisconsin (converted stone quarries and Devil's Lake). I must admit that almost every dive is my favorite. I say "almost" because I have had a couple "not-so-good" ones due to my own comfort level on those days. (My UW navigation dive for the Advanced class had me so nervous that I gulped air like a madman, yet did a night dive later the same day and was as relaxed as I had even been. Also experienced an ear squeeze and tooth squeeze - not at the same time - that made those dives memorable in a not-so-good way.) On every dive I see something I haven't seen before - whether it is a sea creature, or ship/plane wreck, hurricane devistation - each one fills me with such awe that I'm giddy for days.
Snorkeling is about the same too. But, there, I do have a favorite. It was outside of Manzanillo, Mexico, and it was to be a dive. But, since I was the most experience diver of the group (besides the DMs) the regulator they tried to give me leaked like a sieve and the DM kept banging it against the boat. (BAD!!!!!!!) I would have been out of air in 10 minutes. I chose to snorkel with some non-divers on the boat. The rock formations sticking out of the water were actually like short tunnels you could dive down and swim through. They were literally covered with urchins. I had seen many a reef on other dives, so this was a new experience for me. I felt like I was snorkeling through someone's castle.
Speaking of "Open Water" did you see that movie with the same title???
I haven't, and I've been told I better not watch it, if I ever want to go diving again. And snorkeling can be awesome, too!!!
Personal Opinion Alert - (our personal opinion only here)
We've watched Steff. It was a little creepy, but we found ourselves commenting on the "stupidity" of the 2 divers who ignored most of the safety rules for survival once they were "lost". Also, that any dive operation that handled things from beginning to end the way they did - would have lost their licensing long before this trouble started. It did reinforce our want not to do shark dives. (I'm getting too old to play with sharks.) We will have no problem diving again!!! If you decide to watch it, rent the DVD so you can watch the "making of" stuff. That takes all the scariness out of it.