If its in the world your looking for then i believe it is Mount Everest, most closely followed i think if my memory serves me right by K2.
If its in England you want then i believe that is Scafell Pike, Scotland is Ben Nevis (my favourite) and Wales is Snowdon (my very very close favourite).
Of course if you want to take me on holiday i would like to go to the North Face please. And one day we will do Everest Base Camp at least.
xx
Hope this is enough answers!