Went there in 1995. Was an amazing experience. What I liked most was that the island is small enough that you really can get involved in nearly everything it has to offer. Some recoomendations and comments:
1) Baby beach - a very shallow beach over at the East end of the island, near a refinery - but don't be concerned about any refinery issues, it's BEAUTIFUL. A favorite family spot.
2) Golfing - the West end of the island sports a HUGE golf course that has wonderful ocean views. While I am no golfer, it was pretty remarkable.
3) Diving - if you are a certified diver, you have many choices of offshore dives. If you are not, many of the local dive shops have "on the spot" instruction and will take you out for a few hours. I am a certified diver but the dive shop I went to was having an "on the spot" instruction and we joined with a group of newbies. We went just offshore and dove on some old ship hulls. It was incredible.
4) ISLAND TOUR - I highlight this because it was my favorite part by far. You literally take a Jeep up over the center of the island and head towards the North side. The hills are very rocky and craggy, and there are lots of cacti, and many many wild goats in the rocks. On the north shore, the water is far different from the south side. This is the WINDY side of the island, and it is void of beaches and resorts, with very dark, deep water and waves. We were told that the island dumped their food garbage out here, because the waters were shark infested and they loved the scraps.
On the north side, watch also for the natural caves, the natural stone arch bridge, and an isolated pool of water where folks like to stop and swim (the rough ocean is about 10feet away on the other side of rocks). When we were there I got a photo of a sea snake down in the bottom of the pool...a little scary.
5) South side beaches - plentious. If you are a nudist, you will also be welcome. I was unaware of that until I went snorkeling and popped up on some young ladies on an inner tube. Interesting

. Other than that, there was a beach we went to (can't remember name) that had underwater tires/tow lines that you could follow out to sunken offshore relics (planes/boats). Brave? Go for it.
6) Shopping - the central area sports many outlet shops and markets that hold a number of international goods/foods. Have fun there!
Some cautions and suggestions:
1) SUN - man, when you are on the beach the breezes will FOOL you. WE got cooked. I can't say enough about sunscreen. The sun is TOO bright to see the red on your skin, so be warned.
2) FOOD - DON'T expect lots of fast food, it's not there. Stick to the hotel fare unless really sure of what you are getting/where. The hotel buffets are OK, but not exceptional in any way. Food is also EXPENSIVE.
3) STRANGERS - As you are out touring the boardwalks or shopping, there will be solicitors with offers for timeshares, prizes, presentations, etc. Be warned - and be weary. You are in another country.
4) ENVIRONMENT - If you DON'T know, Aruba is a DESERT. I am not kidding. I could not believe, when we landed, that I was in desert replete with sand, cacti, and rocks. It's very, very dry and hot, it may surprise you.
I know that's a lot to consume. Hope it wasn't too boring, and was helpful. I wish you a safe and enjoyable trip; it will always be remembered as a favorite.
CHris