As wide as possible *resolution wise) is the way to go.
But like others have said - Pixel size on a monitor of the same physical size is smaller - which can make things harder to see.
I love the wider field of view, being able to glance without turning head for TrackIR.
After a while, the bezels between the screens are not actually noticed.
Three, three year old 27" Predator XB271HU's running 7780x1440