@kungfujam Yes, with the updated color tables, I'll say this one gets very close, I've done pics A/B of 5000K and 2700K and they are EXTREMELY similar. The f.lux team is very busy so it won't be soon that they update.
I don't think f.lux on Linux works with multiple monitors, so they'll need to fix that as well.
The only thing I really miss is Photoshop, other things i've got covered with as you say, equally good or better apps. Even games are starting to catch up, usually no big titles, but still.. good enough games for me to stay on Linux.
Same goes for my gf. If it wasn't for photoshop, her laptop would already be under linux.
@Amit-Patil Ah, you'll want to (maybe not want to, but it will work better) use the newer f.lux daemon below those install instructions, called xflux. It's easy to run. Also search the linux forum section and you'll find more information here.
Since you say, you should do a version for RPi, are there already any plans for doing that? Or is it just an idea at this point? Just curious, cause I really like that awesome piece of software and using it on my Windows system, but have an RPi as a media centre.