Personally I still see 1440P being the sweet spot in performance and visuals and value.
I've got to admin that even I'm moving towards that more and more. I still think 1080p makes sense, but the appeal of 1440p definitely keeps increasing. After a 22" monitor, my current 24" 1080p seemed to have awfully large pixels, but I got used to it pretty quickly. Still, I can't really see myself going for 1080p if I end up getting a larger monitor, which might just happen when I do eventually get a new monitor (which shouldn't happen in at least a few years though, unless my current one breaks). But still, 1440p seems like a bit of a necessity for screens larger than 24", but it does make sense for smaller monitors.