I thought cutting off the sides then enlarging going from 1080 to 1200 was game-specific, but I just tried it with a few games and they all do it... What the hell man? Do any games have a vertical FOV option?
TF2 1920x1200
TF2 1920x1080
TF2 1600x1200
AOE3 1920x1200
AOE3 1920x1080
AOE3 1600x1200
Skyrim 1920x1200
Skyrim 1920x1080
Not sure what the deal is with the time of day or weather change here. I didn't do a 16x12 for Skyrim.
Stalker 1920x1200
Stalker 1920x1080
Stalker 1600x1200
This is why I don't bother with the screen ratio debate. I simply went with a 1080p 16:9 monitor a couple years ago because it was affordable to do so. The main game I play happens to be Team Fortress 2 (which I also play competitively), and I have ~3100 hours total in it. Your testing proves that TF2 at 16:9 is superior to the other aspect ratios, and I'd imagine this is applicable to most if not all other Source based games, and that is what matters to me.
There are 169 1080p monitors and 20 1200p monitors currently available on Newegg. 1080p monitors start at $109 and 1200p monitors start at $280. Being snobby and paying a ton more for a probably outdated 1200p monitor just because "it's 10% taller" is a rather crappy argument. In fact, for slightly above the price of the cheapest Samsung 24" 5ms 1200p monitor, you can get a 23" ASUS VG236HE which is a fantastic 2ms 1080p monitor that has a 120Hz dual-link DVI input and the nicest TN panel I have ever seen. 5ms TN panels are so 2005, and I would not drop $300 on one.
How about some pros and cons for 16:9 monitors?
Pros:
Cost effective, lots of models on the market.
Standard aspect ratio for HD movies released on consumer mediums. (seriously, guys, everyone considers scaling evil, so how is scaling your 1080p movie to 1200p suddenly acceptable?)
Most games support 16:9 well, since many are ported from consoles played on 16:9 TVs.
No black bars on fullscreen 16:9 content, which is basically most entertainment content nowadays.
Potential ~10% performance increase in games (because you have to render 230,400 extra pixels on a 16:10 display, and chances are your game will still chop off your sides to fill the extra height up).
3D or 120Hz models readily available.
Cons:
Less desktop "height" (but if you have some document fetish and are so concerned with 120 pixels of height being gone, you should really consider a professional 27/30 inch monitor if you are scared of zooming out).
If you're doing any work that you are going to gripe about not having enough space to work with, get a higher resolution monitor. Plain and simple.