I think it would be fine on a dresser, if it well-made and sturdy. Of course, a cheaply-made, pressed board, flimsly dresser isn't going to be safe, but an older, well-made on is going to be fine. When I lived with my parents, I had a 30 gallon tank on a big wood dresser for ten years. It was perfectly fine.

I then had a 30 gallon tank on a big entertainment center for years. Now I have a 55 gallon, and it is on it's own stand. It is the stand that was made for this tank and purchased for it. I got it at Walmart, and it's very sturdy. It is held together with cams, not screws or nails. I think that helps, cams are a very sturdy means of construction.

Aquariums are indeed very heavy ... a 30 gallon tank has 240 pounds of water alone, plus the weight of the tank itself and the gravel. I would just keep that in mind when choosing something. I think you'd be happier with a tank on a stand then on the floor, personally. It would be more pleasing to eye on a stand, IMO.