I am aware of the HMS Victory, that would be Admiral Nelson's ship.
There is the Britannia, which I think was both steam and sail if I remember right. The HMS Trinncomelee (however that is spelled) that I think is one of the oldest ships to still float. You have the Holland, an early Submarine. There is the Mary Rose but I don't think that counts, it is not what I called preserved. Everyone has heard of the Queen Mary. There is the HMS Gannet and there is the Warrior, and Belstaff. I can't think of any more.
I still think the HMS Warspite was as important not for single acts or for what it was but for how often it did things and how much it went through over and over again. I think one of the great stories of a UK ship was the Rawlaphindi (spelling again). That was a story of guts in the face of certain doom, well she failed but that was expected. Then there is the Campbell town, an amazing story there too.