I know and read a number of people who use laptops as their primary machines, but I'm one of the people who's not interested in the idea (even ignoring any issues of relative prices). I wound up actually thinking about the question recently, and as it turns out I think I have a fairly odd set of reasons for it.

So, here they are so far:

• I have very particular tastes in keyboards (I have used a BTC-5100C keyboard for more than a decade) and for the space immediately in front of the keyboard. Laptops may have decent keyboards, but they don't have my keyboard.

• I want a fairly physically large display with good resolution, especially good vertical resolution; when there's room for it, I want two of them.

• I use two drives in my systems in order to have mirrored (system) disks. (Of course this can have drawbacks.)

In the past, my desire for Unix (ideally Linux) would also have been a significant obstacle, but my impression is that it's now relatively easy to find a nice modern laptop that has good Linux support. (Hopefully I'm not wrong.)

Another way of thinking about this is that I have two roles for computers: the computer I sit in front of all the time, and the computer that I take places for relatively moderate use. For the heavily used computer, I have strong and very particular opinions about the pieces of the computer that I interact with a lot (the keyboard, the displays), but I'm indifferent to the rest of it (provided that it's quiet). I don't care as much about the casual computer, but I want it to be small, light, and still nice for productive work.

(The late Dell Mini 12 is about my platonic ideal of the casual laptop in form factor, screen resolution, and keyboard.)

It's pretty clear to me that some of these desires clash even in the best of circumstances, particularly the displays; a laptop screen big enough to be one of my regular displays makes the laptop too big to be conveniently portable. Thus, if I tried to use a laptop for both roles the only use I'd get for it in the full time usage role would be as the system unit of a desktop system, as I wouldn't use either its display or its keyboard (and I'd still only have one system disk). If I absolutely had to have only computer this could be workable, but if not, there's little advantage to it.

I suspect that other people are generally much less particular and picky about their keyboards, displays, software, and so on. (Or, alternately, they have found a laptop maker whose keyboards and screens they are as fond of as I am fond of my favorites.)

(This entry was sparked by the discussion here. Plus, I feel like not writing about documentation for days on end.)