I manage Unix systems so having it be wide screen helps with longer lines.
But I also write code so having a portrait screen helps when I'm reading documentation (PDFs for example)
Well I have managing and configuring Unix systems since 1981 and Linux since 1998.
Be it a tty or even a printer (and yes you can do this) you can write programs, in fact with a GUI it becomes even easier to write programs, however no matter what you use unless your display software is really stuffed you have what is called "line wrap" so you can always see what you wrote.
Using a GUI can let you configure a window to any size within the confines of the physical display area. In fact with a decent display manager you can set up virtual screens which are very easy and fast to switch between. Over the last 16 years I have been using KDE and Xfce to do just this. Going back to the early 1990 I actually use CDE to do something similar.
So I have a four monitor setup. Two Landscape (one reversed above my number 1 landscape monitor) and Two Portrait; one to the left and one to the right of the two center monitors. Works well for web browsing and coding where I want more side to side screen space and gaming and works well when coding and I need directories to the left and pdfs to the right. The top screen has my debugger or Firebug if I'm working on a web page.
Nice a 4 monitor setup. The problem with this is you are not very portable but then again that is your prerogative. As for multiple screens this really depends on what you are doing and how efficient you are in managing the displays. Four screens IMHO is definitely over-kill but to each their own after all it is your money.
As I mentioned before I use KDE and I have setup by default 4 virtual screens which I can add too or subtract in about a second. Switching screens normally takes a second and since I have a high performance laptop I am very portable although I can easily plug in a larger screen if I so desire. If I was using a desktop PC which had limited portability I would still use a single landscape monitor although I would make sure it was above A4 in height which for a 16:9 aspect ratio is 24" and above.
Ok I am going to demo some real world examples. I have a 17.4" 16:9 aspect ratio laptop and I am going to write some code, how many lines do you think I actually need in the window where I am going to write my code? How does 79 rows and 261 columns with wrap around sound? Don't like that I can still increase the size although of course I can go smaller as well. How about 24 rows by 80 columns (standard tty screen cira 1975)? I can even have multiple tty windows if I wish or smart GUI editor windows.
Using the same screen I am going to display a PDF file. Displays fine however because the hight of the screen is smaller than A4 so I have to use the scroll wheel of my mouse to view it fully although I can shrink it to fit keeping perspective. The same is also true for web page and since I use tabs I can have multiple webpages on the same web window. This really begs the question "Is this a problem?" and if so "Why"?
I have posted before on what I consider stupid articles that try to show (IMHO poorly) that Portrait is better then Landscape. The choice depends on what your requirements are however in the majority of cases Landscape on a reasonable sized display is a compromise but it is normally is the best of all worlds. Sure when displaying full sized A4 you will have some "real estate" that is not used up but again is this such a big deal?
Having made my rant I still will state that a Landscape monitor is better than a Portrait monitor providing the criteria I mentioned before is met.