You'll love the park, and the area. We live maybe 70 miles from Hershey, and visit a few times a year. It's a very nice park; clean, friendly, nicely laid out, with a good assortment of rides and attractions. The area close by, as others have said, also has the Hershey Gardens, tours, shopping, quite a bit actually.
As far as thrill rides, while not a CP, they have their share of decent coasters. 3 really good woodies, and at least a half dozen steel. (Storm Runner being my current favorite). Check their web site and I think you will find something for everyone.
With that said, Hershey expanded their waterpark area this year, The Boardwalk, by adding a new wave pool. It's a nice area, but "inside" the park itself. If you plan on using it, you might want to bring a swim bag with you, so you can easily change in the parks changing area's. Also, I have not looked lately, but if you plan on spending more than one day in the park, I think you can add a 2nd day to your tickets for like $10 per ticket.
Also, don't miss the chocolate factory ride\tour right outside the park. It's free entry for the building, which inlcudes the ride, restaurants and shops. There is also a 3D movie, costs extra, but worth seeing if you have not been before.
Other than those few things, I would say have a great time! It's a really nice park, and a lot bigger than you might think. Definitely a good day or two for anyone!