I'm traveling with my 19 year old daughter (going on 30). We have narrowed our islands down to Aruba or St. Maarten. We have found reasonable flights for both. Now we need a reasonable hotel. (don't go off on what is reasonable--if you don't know then you have too much money--I have two kids in college I want the trip as inexpensive as possible, with clean rooms and decent service!) I almost booked us at a nude beach so I really need suggestions. We want to take some boat excursions, get away from the resort,etc. YOur suggestions are greatly appreciated!

I think Aruba is a better overall destination.
Aruba:
better beaches
nicer weather
safer
cleaner
friendlier
nicer resorts

ST Maarten
more culture
better gourmet restaurants.

moderate priced hotel choices
Holiday Inn or La Cabana.

really moderate choices include Brickel bay, Mill, talk of the town and Divi Phoenix.

St. Maaretin is my choice. Add low priced car renting, great beaches, great food, excellent snorkling, easy on the pocket, plus inexpensive ferry's to St. Barts and Anguilla. You'll want to return for sure.

I have to disagree with patsfan.
St. Maarten definitely has better beaches than Aruba, and more of them.
when you say you almost booked at a nude beach, I assume you meant at Orient Beach.
That area actually is a very nice area to stay in.
Orient Beach is clothing optional and only at one end. You will not see total nudity on the whole beach.
St Maarten also has an advantage if you want to teak boat excursions. There are several islands near by that you can go to for the day.
All of the above being said, I love Aruba too. My preference is St. Maarten but i am sure you would enjoy either island.

If your daughter wants a bit of a social scene then Aruba is far better. Overall St. Maarten is much more laid back. I would say Aruba is more commerialized and can be less expensive for a decent accommodation but the beach at the hotel will likely not be that nice. There really is no decent snorkeling in and around Aruba or St. Maarten. Curacao is the place for that in the area.
Easier to get away from the resorts in St. Maarten but while neither is my prefered destinations we think the food is better in STM but the island is a bit boring and we were there in our 30's, late 40's and late 50's.

the island is boring? that is so funny. people come to SXM because it is NOT boring. there is so much to do.
day trips to other islands. french side and Dutch side. fantastic dining.
clubs
live music.
ziplines.
beach bars
America's cup sailing races.
I could go on and on. LOL
SXM is not for everyone but it sure isn't boring!

all due respect but i dont know anyone that thinks the beaches in st maarten are better than Aruba's beaches!
Eagle and Palm beach are both nicer than Orient or any other beach on ST Maarten.
If you had said Anguilla or T&C than I would agree with you there but not SXM.

Now if you want to compare the dining or the culture than ST Maarten is a touch island to beat in those categories.

you don't know anyone?
well, even my Aruba relatives think St. Maarten has nicer beaches and many more of them.
and just ask any St. Maarten resident, many of whom are native Arubans, what they think!
Eagle and Palm are beautiful but that's it. ST Maarten has over 30 beaches, all beautiful.
but I do agree ..the one that beats all of them is Anguilla.