I'd start with Pandora's Star, they are HUGE in scope, so its a big book but worth it IMO.
I'd start with the Night's Dawn trilogy, I've read most PFH except for his last few and those are my ATFs.
I've found the Mandel Trilogy to be entertaining, too. Could be thought of as some world-building for the much later ND? But not as epic. Just three normal paperbacks.
Night's Dawn was the first Hamilton I read...and I've read it once or twice since.