I would advise two more GB's, but you yourself must exercise caution when building them. The first one is Hagia Sophia. It's a good bulk happiness booster and gives you a nice income of FP's, but be careful because it is a huge building. The second one is Chateaux Frontenac. 5x6 is not much for a GB these days, but they're only useful once you finish the entire tech tree and begin doing loop quests. You can, of course, get it just for getting more goodies from quests, especially the pitiful diamond rewards.
If there is one more GB I would add to byeordie's list, it would be Frauenkirche of Dresden. Takes some time to level up, but it currently has the highest happiness per square value of all GB's (even higher than SN), and it gives you a pretty decent amount of goods. For this reason, you should avoid Notre Dame if you can and use those HMA goods to get a St. Mark's. It is one of the best GB's in the game.
If you want more resources regarding GB's, you should read
-Vanguard's.- guide for every single stat on every single GB there is in the game. If you want a fresh perspective,
davidb3's guide analyzes every GB until the Progressive Era and, if you have the time, read the spare posts found in the thread itself showing other players' opinions from different standpoints.
There is so much information on Great Buildings on the forum. You just have to dig it up. These two threads give you nearly all of the information you need on GB's.