Not sure about that PSU wattage usage ... few weeks ago I had a digital power meter connected to the power of my computer(s).
Running CloD, its usage went up to about 450W, (I think I got a 650W PSU in the pc), in idle/browsing mode it was about 180 to 200W, depending on having a secondary monitor switched on or off. (Note: the meter was catching not just the PC's power, but also all other equipment (incl. a light bulb, a modern one).
One would not expect a 750W to be using more power in the same situation...
(I have not tuned my system to be power sav(v)y ... I think.)
As for how long CRT's last vs. TFT/LCD I think it'll be a close call.
Got a feeling that the flat screens last even longer than CRT's (currently, at work, I see very little of them fail, I think less than the CRT's in their days...)
Also, please do realize that the monitor is the most important thing here, you will be looking at it a lot.
It is your main interface with the virtual environment!
Widescreen is what you want, much better in flight, you see more of the air!
Up to a certain point, bigger is better, but resolution is also important, they are closely related.
Just this week, I heard someone being happy with a 40" TV Screen, at 1920x1080.
Dots were a lot bigger, and indeed easier to spot. Yeah, why would that be?