Hi! I posted a reply here yesterday, but it seems to be lost....oh dear! I know all about Anguilla, and would be happy to share ...one point though, there is definitely no rain forest on Anguilla, in case this is a major consideration.
Feel free to email if you would like more info on the island....it's gorgeous!
I know about the other two islands you mention, but haven't visited either, so hopefully you will hear about them from someone with direct experience
Jill

My husband and I were in Tortola last year and Anguilla the year before. Both islands are lovely and quiet. Anguilla (car necessary) is more upscale and expensive (super restaurants) than Tortola, although Tortola is more lush (jeep rental recommended). Both are very beautiful, but neither has great nightlife. We found Anguilla to have a more 'couples' crowd, with Tortola having a more 'family' oriented crowd. It probably depends on the time of year. Either way, you can't lose!

I've visited all three islands. Anguilla is very very flat and therefore absolutely know need for 4wheel drive (car necessary). Has caves that you can discover and beautiful beaches, great snorkeling, scrumptious but expensive dining (can recommend self catered villa to keep dining cost down. Not much in nightlife except for Johnno's open air beach parties or hotel entertainment. The island of Tortola is beautiful in comparison to Anguilla but does not have as nices beaches as Anguilla but their beaches are nice at any rate. It is very mountainous and depending on where you will be driving, it will require 4wheel drive. The town (Road Town) is getting very busy. Several local spots for dining. Not much in night life but more than the other two islands. Like Anguilla, this is also a very safe islands.
Of the 3 Nevis is the most difficult to get to. You would fly via San Juan and St. Kitts then ferry link or 5min flight to Nevis. This islands does not have much. Like all three islands, the people are very friendly. Nice dining and not much in the way of night life at all. You have chosen some of the nicest islands one can travel to for peach and tranquillity. If I can be of further help to your or anyone else, please feel free to email me.

You mentioned that you are interested in scuba & snorkeling. We snorkeled in Anguilla which was only so so. We also scuba-ed in St. Maarten which is VERY close to Anguilla and it was not memorable at all (indicating that scuba around Anguilla would as well perhaps not be great.) We absolutely loved Anguilla though for its beaches and serenity and nice people and can't wait to return someday. Never saw as many stars in the nighttime sky anywhere else in the world as we did there. The snorkeling in the virgin islands (us & british) is great - esp. St. John - maybe Tortola would be too - maybe someone can reply to this. What a dilema to have!

I have done alot of research on renting a home in the caribbean. St. John sounds like the perfect island for your family vacation. There is a large selection of homes in every price range. Here are some web sites to get you started- www.caribbean.com, www.cateredto.com and www.destinationstjohn.com. Good luck in your search.

Laurie

Sorry, made a mistake on one of the web sites- www.caribbean.com is www.caribbeanvilla.com

Laurie

The Best place we have found so far for a family or anyone is Grand Cayman atThe Garden Houses of Cayman Kai. They are about 45 minutes from civilization. Private houses right on the beach plus a pool. The beach is heavenly. The houses are 2 stories with all the luxuries. A true paradise.