I think 16:10 strikes a nice balance, particularly on laptop displays. It's wide enough to handle a couple of side-by-side windows well without feeling particularly starved for vertical pixels.

For large monitors though (27"+) the need for width is reduced… I've never used a 4:3 or 5:4 monitor that large but I don't think it'd bother me nearly as much as those aspect ratios at small sizes do.

I think you mean 4:3