I still weep for my old 21" Sun CRT monitor I had been using up through last year some time. I loved being able to hop down into really low native resolutions when doing stuff like DOSBox and the like. Alas! Still, I do love the increased clarity available on my shinier LCD, though.
I need to tick the box for the traditional 17" screen, as that's what I've got, but looking in the shops I see mainly widescreen now. As you were already seriously thinking about widescreen support, I would certainly go that way.