Liveaboard is so heavily marketed to the North American audience, that will be the bulk of recommendations.
i have done it by several liveaboard trips, but the last three time we did land based out of Puerto Ayorra. My divers get to see Hammerheads and Mobula Rays, plus they get to really enjoy their time ashore exploring to town, The Darwin Research Station, the local restaurants, plus the two lava tube adventure crawls. They enjoyed the 1/2 day trip to the highlands to see the Turtles in their natural environs.
For land based, there is no comparison for Scuba Iguana. We like the Red Mangrove right next door, both at the gate to the Research Station and a ten minute walk to the small business district. They will show you enough Hammerheads at Gordon Rocks, they will move their boat to the far North (near the airport), and drive you up there to meet after breakfast at a table that isn't pitching to and fro. There's something to be said about beds that don't rock, as well.
In light of your dive history, that might ring a bell for you.
The Galapagos is one of the very very few dive destinations where I suggest that divers do something besides sit in a rocking boat and dive. Yes, the diving around Wolf and Darwin islands is grand on any scale, but you are signing up for 2x18 hours of bouncy crossings out of your time.
There has been a torrent of liveaboard corporate and mechanical failures as of the last four years, charters disappearing overnight. Choose with care if you go that route.
