Re: Recommendations wanted - space opera/ big idea sci-fi
A word of warning Hamilton's Void trilogy (Dreaming, Temporal and Evolutionary) follow on from his two book Commonwealth series. It is set some time later and although it is a totally separate story it does have some of the same characters in it. I suspect you would be better off reading the two Commonwealth books first: Pandora's Star and Judas Unchained.
As far as the second question goes. It would be hard to know where to begin there are so many. My earlier post (#6) had a couple of suggestions that weren't quite space opera and then there's PKD; his books tend to be quite small but his ideas certainly aren't!