Personally, for me its 6700M (22500ft+) but don't really care about how high I can go unless its a good technical climb and if the objective is gorgous, all the better. For me thats why I'll be in Nepal in the fall to do Ama Dablam (not a hard objective but damn gorgous) and then a significantly harder, gorgous peak at a lower altitude.
Have to agree, there are beautiful mountains in Canada (the Waddington Range, the Candian Rockies), Alaska, the Alps and in Peru and Argentina, which are all more affordable then the "Greater Ranges".
As for me I like to explore what I percieve is my limit (and my perception is usually wrong) usually in a technical or mental sense. I've always been an endurance junkie so my mind is pretty open to not having limits there.