imho 24' is to small for a "large gaming monitor" if you want to upgrade from what you have now. 27' or 28' is a better size, and you can keep it at a similar resolution 1920 x 1200 (so you are pushing the same amount of pixels)
going to 30' with its much higher resolution might look good for desktop uses, but for gaming it is an incredibly high pixel count to try and drive
the new 27' dell with the higher resolution (2560 x 1440) looks like an amazing monitor (and much better then the 27' dell i have been using the last few years), BUT it basically has the a similar amount of pixels as the 30's models, so will need a monster pc to run at decent frame rates in BoB
my suggestion: get a good brand 27 or 28' monitor that runs 1920 x 1200 if you want something bigger then you have now. and if you want to expand from that you can add a cheap 20' on either side of it later (they have the same physical height and resolution) and significantly improve your peripheral vision in BoB (from 55 FoV to about 110 FoV). the total pixel count of one 27' with a 24' on either side is still only roughly the same as one single 30' and that would be a pretty amazing setup for a flightsim
