I'm a long time Civ player but a first time CTP player. I've been playing steadily since CTP2's release.
The tech tree in CTP2 is huge! Any advice on what are the key wonders/techs? Anything from CTP1 that is of help?
In Civ, I always went for Great Library, Leonardo's Workshop, etc. I haven't found any equivalents in CTP2 but right now I work towards those wonders that don't expire (like Hagia Sophia).
Get them all it seems easy enough... Seriously The wonders in this game don't seem to have a game altering dramatic effect like some of the ones in civ 2...there were some in that game i remember you just quit and start over if you were beat to them..and I am a Civ Diety player..but haven't played for a good 2 years.
I would say I like happiness wonders in general (a habit I admitedly developed in Civ 2 since i played diety you can understand =)). I also like science wonders like Aristotles Lyceum because I am a science freak and like to stay well ahead of my opponents in tech so i cna smack them down with ruthless effeciency ;o)
The wonder that decreases crime by 30% is my favorite, but also the Ramamaya (sp?) +3 Happiness everywhere.
This helps with cities far from home and, and/or enables you to push the workday to 14 hrs (useful in early game; less so later due to pollution.)
Later, the Central Matter Decompiler -- less pollution in all your cities. Akin to the Civ2 Hoover Dam, but no production bonus.