A widescreen 27" monitor is fine for portrait windows. I typically have some terminal windows, web browsers, and PDF windows open, and most of them are portrait. The advantage of the landscape monitor is that I can fit them side by side easily. There's easily space for a couple of portrait-A4 windows on the screen for documentation / procrastination and for my terminals floating either below or between them.
The main reason for landscape monitors is that most humans have two eyes that are next to each other. This means that they have a field of view that is much wider than it is tall. You need fewer eye (and head) movements to see all of a wide monitor than a tall one.
I think that only applies if you drink coffee black
Coffee is black. Milk with a hint of coffee bean is an entirely different drink. Places like Starbucks put a lot of milk and sugar into their drinks to disguise how bad the coffee is, but if you get a decent blend (I'm particularly partial to 50:50 mocha and mysore) then you have a rich - and not too bitter - drink that you can sip enjoyably.
More importantly, it prevents the creation of new and innovative players by anyone other than the existing manufacturers. In under 20 years saw the normal way of playing back music shift from shiny disks to tracks on a large storage device. We haven't seen the same shift for movies, because they had tighter DRM and so there was nothing like iTunes for DVDs (open source tools exist, but any time they are shipped in something that looks like a commercial product the studios sue the manufacturer out of existence).
They are called computers simply because computation is the only significant job that has so far been given to them.