I love them all! Is that a good answer?
I love them all for different reasons though...I loved francis for its amazing snorkeling...turtles, stingrays, GIANT starfish...just watch the little biting critters after noon..ouch
I love hawksnest, because it's no effort to get on the beach, and you can seek shade by sitting in the trees.
I love Maho because it's so so so very calm, beach is short so not a lot of walkers...just nice.
I love trunk, it can be busy, but I have been there several times when it's not and there are a million sea friends around that path, and we saw more hiding even further out, stingrays!
Although its not a beach, I do love a snorkel in Hurricane Hole...AMAZING!

my vote - jumbie !

I really liked Maho. We spent a lot of time on this teeny tiny beach over by Vie's (which I guess is also owned by her family) that was perfect for our group of four, although the bottom was pretty rocky. It looked great for snorkeling, though, and the water was great.

Gotta love the sunsets from Maho...

Honeymoon, Salomon, and Denis Bay are incredible - All require a short hike, but well worth it!
If you don't want to hike - I vote for Francis Bay or Hawksnest.
It's hard to pick because they're ALL gorgeous!
Here's Denis - always so crowded!

I don't remember why we didn't wait at Maho for sunset, but it's on my list for next time.

I just was introduced to Honeymoon last week, and it's my new favorite. (I guess they usually are, until the next one.)

What I like about it is that the sand and the water reminded me of Jost Van Dyke (my other favorite) more than any other beach I've been to. Also, you have St. Thomas in the background, unlike most of the other beaches. Not good or bad, necessarily, but different from the others, except perhaps Caneel.

(By the way, to get to Honeymoon, pull into the Caneel resort. Stop at the little guardhouse, then tell the guard you're going to Honeymoon. If you don't know where the path is, the guard or anyone else will show you. It's very easy.)

We also returned to Hawksnest this time, after not really being up for it the last couple of times for some unknown reason. We liked it much more than we remembered.

Another favorite (hey, I can have as many as I want!) is Leinster, although it let me down last week. We promised our friends it was worth the walk just to see the starfish. Of course, there was not a starfish to be seen. (In fact, we didn't see any on our whole trip.) Still, the snorkeling around Waterlemon was as good as I've seen it. We also saw two cuttlefish/squid (some debate on this point) there, which were cool.

I agree with Blue about Salt Pond. The first time, I loved it. The second time, it was fun but didn't seem to be worth the walk back. The third time, we weren't at all interested in going.

Of course, White Bay is my absolute favorite, but it's not technically on STJ. Well worth a day trip, though!

We just hit the high points this trip, but next time we plan to head off the beaten path a little more...

OK, i've taken my poll and it's so close. I guess all the beaches are so great, that you really can't loose, but here's the tally

Honeymoon - mentioned 5 times
Maho - 5 times
Frances - 4 times
Jumbie - 4 time (we did go there, found it by mistake :o)
Hawksnest - 4 times
Gibney - 3 times
Salt Pond 3 times
Salomon - 3 times
Little Cinnamon - 2 times
Waterlemon - 2 times
Leinster - once
LIttle Lamshure - once
Denis - once
Trunk - once
Hurricane Hole - once

Thanks everybody!

I never went to a "bad" beach while I was there, but I do have some that I like more than others. For example, Hawksnest, which a lot of people mentioned as a favorite was just another beach to me. I like them all for different reasons, and I think that the policy of going to at least one beach for a little bit every day is a great one for your trip.

Hey!
I love snorkeling at Leistner that place is ah-mazing you see turtles almost every time and starfish. Lots of crabs too.

Some of my favorites haven't been mentioned at all. It doesn't surprise me because part of what I like about them is that they're not very popular (i.e. crowded). We always get to Haulover--good snorkeling, although the beach itself is rock/coral. And the East End beaches---Vie's and along Hanson Bay around Pelican Rock.

ALL St. John beaches are world class, bar none. It just depends what you're into. MAHO BAY and Francis BEach are good party beaches. Cinnamon and Hawksnest are family type beaches. Now people will tell you that the best snorkling is at Trunk Bay. Well if you want to pay to get in and follow a cool underwater trail, then I say go for it. But if you wanna REALLY SNORKEL, go to LEINSTER BAY and SALT POND out past Coral Bay.