[Cougra]

Anemones are very demanding creatures that do require prestine water conditions and a lot of light. I think the two things that most people forget are :
1. They are mobile inverts. If they don't like the place that you put it, it is going to move. It doesn't care if there are other animals in it's path or that you had planned to have something else in the place it chose to live, if that's where it wants to live then that's where it's going to live.
2. They are predators. They will eat other fish or inverts if they can catch them. If the anemone eats your prize $500 fish, well that's what it would do in nature as well. You can't train them NOT to try eating something should the opertunity arise.

Personally, I don't like seeing them sold in stores as most of them end up dieing a slow death. In nature they can live hundreds of years, in a tank their life expectancy is a dismal 1-2 years. Yes I know there are "success" stories that someone had it live for 5 years but how many others have died? If they are wild caught, they are very delicate animals that are doomed to death before it even arrives in the store due to poor collection pratices, the stresses of holding and transportation, and physical damage from mishandling (merely touching some with your bare hands has the potential to burn them because of the pH differences).

Before you get an anemone, learn as much as you can about keeping a reef tank in balance, make sure you have all the equipment necessary to keep one, and do as much research as you can on anemones in general and the species you are interested in specifically. Don't assume all anemones are the same because they aren't.