I went with a pair of the 2311s for about 500 eur and they are very nice. Nice little screens that offer you a good image, lots of desktop space and flexibility due to the low price and portrait mode - can easily fit at least 2 browser windows on top of each other, it feels funny, a tall and narrow screen in portrait mode because the height of the panel is only 1080 pixels. Still have to install Linux and try out the Awesome window manager - I figure I could easily manage some 100 windows/tabs with its advanced WM concepts.
Images feel relaxed and natural with this monitor, text is sharp with little colour bleeding (seen some cheapish TN screens which are way worse), rather enjoyable screen overall. Sure money can get you closer to perferction, and I might not notice the difference even here but certainly this is good enough for me and then some
23" screen is nice for general purpose use. For me the text is readable even at a slight distance. I sit a bit away from the screen as I currently am using it in a 3 screen setup. Maybe a 24-30" screen could offer a bit more immersion and oomph. But I can very well do all I want to do with these screens, so the U2311H seems to have been the right choice for me.
Overall I suppose it meets almost all the criteria I specified:
High contrast -
haven't actually tested this too much, feels nice but I suppose so do most modern screens
Color depth -
check - this is 8 bit
Wider color gamut could be nice -
just normal color space on this screen
Power consumption should be <50W, I think this means LED screens -
U2311H delivers here too, seems to be typically 34W for me, sleep mode is near to zero
Less important factors:
Stability of the base (and general robustness) - so the monitor is not as easy to knock over -
looks good here; visually the design is an elegant no-nonsense black, goes well with my Sonata case I guess, even the blue led colour matches
Response time - I think I'm looking for a quote of 5ms, but if there is a measurement on black-white transition, faster is better -
good enough here, not an issue for me when playing FPS
Portrait mode (tilting monitor) available -
check
1900x1200 could be a nice resolution (but I have some concerns another 1900x1200 screen would be hard to find when 1080p is taking the market by a landslide) -
only 1920x1080, but at this price one has to prepare for compromises
The monitor comes with a display port too, so it's easy to use for triple screen setups. (No HDMI, but I don't need that.)