well if you didn't get into lain I'd skip technolyze, despite that being the closest to Ergo proxy, the whole thing is one big "huh?".
Noein is as stylish but a bit more err.. shonen than Ergo proxy? (might get told off by fellow nerds for that one), Might put you off if your going for dark, adult and clever.
Give Real Drive ago as well, though if you found SAC hit and miss youl probably feel the same and more about Real Drive.
Deary me, I'm destroying my own recommendations here. Problem is though IMO as far as dark, intelligent Sci-Fi Anime goes it's rather hard to top Ergo Proxy. Theres probably somthing I'm missing.