I've always had a felt for city building games having played since Simcity 4 first came out in 2003. imo the genre does not need great graphic - it needs great content, Song of Syx is one of my more recent (~2 years) favorite, having a city building game unable to run with the best video card is baffling at best.

I still consider Simcity 4 with full mods and addons the best ever, but for some reason the industry doesn't seem to make similar titles any more, the newer city building games focus on details but gives up on scale.