I literally put thousands of hours on a IBM thinkpad A31p. Enough hours
to polish the keys smooth. As mentioned before the keyboard quality was
key ( couldn't resist 8-) ). So Lenovo/Thinkpad is where I'd go again.
I have also put a lot of hours on Dell XPS 15 inch laptop that has held
up to constant use. So I'd look there again for another laptop.
Brock