I tend to prefer 14-inch machines. My main laptop is a ThinkPad T400 -- it ends up weighing about the same as a 15-inch MacBook Pro, but has just an ever-so-slight advantage in the footprint department.
Older ThinkPads can get hefty, but they're well-built for their time. I've got a T30 that was manufactured in 2003 (Although its model was introduced in 2002) that actually meets 2005's high end PowerBook G4s in benchmarks. I have Windows NT 4 on it at the moment, but there's a good chance it'll receive Windows 7 or 8 if I ever bother to get a newer disk for it.
Regarding the computing power and display size divide: The ThinkPad X220 is a fairly powerful tiny computer, and there's talk about whether or not Apple's going to migrate all of its mobile products into air-like enclosures -- but it's definitely possible to get low end 14 and 15-inch notebooks. (Not quite atom, but why would you really want an atom in something so big anyway?)
Older ThinkPads can get hefty, but they're well-built for their time. I've got a T30 that was manufactured in 2003 (Although its model was introduced in 2002) that actually meets 2005's high end PowerBook G4s in benchmarks. I have Windows NT 4 on it at the moment, but there's a good chance it'll receive Windows 7 or 8 if I ever bother to get a newer disk for it.
Regarding the computing power and display size divide: The ThinkPad X220 is a fairly powerful tiny computer, and there's talk about whether or not Apple's going to migrate all of its mobile products into air-like enclosures -- but it's definitely possible to get low end 14 and 15-inch notebooks. (Not quite atom, but why would you really want an atom in something so big anyway?)