I think it really depends on where you work. The last thing anyone wants to do is spend their lives commuting all over Cairo. they all have a one person to one car policy in this city!!!!
Also, it depends on your lifestyle. If you are young and want to socialise and meet other young people, you don't want to live in Rehab.
If you have kids, then Maadi is a horrible place! Like you say, the roads are a manifestation of Hell and there are scum bags in every cm of all of Maadi. Degla is grim and seems to be becoming more and more dangerous! I lived there last year.
I like Zamalek, but I would only live there if I worked around Downtown. There are pavements. I'm not sure there are pavements anywhere else in Egypt...anyone know of any?
Zamalek is Cairo's 'best area', but there are lots of grey, ugly buildings, which look like drug dens and garbage or cars on the pavements, so you often can't walk on them.
The sun shines on Egypt and it makes things bearable. I wonder if one day it will say "khallas! I'm leaving!" and float up to Scotland for a lovely change of scenery.The sun will always shine on Egypt and its people to continue their daily scene of survival, and Scotland will stay cold and bleak forever.
There is 196 countries in this planet, I advice anyone who can't adapt on this environment to search in one of those and am sure you gonna find one with pavements !!