Almost any of the fantasy RPGs I've played such as Dragon's Dogma, Skyrim, etc because although each has their own lore, other than buildings/inhabitants they are basically the same components cobbled together. A land where you get to climb snowy mountains, run along beaches, soak up the grasslands, get lost in forests or buy shit in a town. All villages are a handful of buildings, most of which you can't enter, and there are always plenty of underground things too. Amalur did go one step further than Azeroth in terms of fantasy stuff like glowing plants, but other than that they are basically yet another selection of Earth's basic terrain types.
I'd agree with Jo and say Pandora stands out because it hints at the corporation wars going on in the background, technology levels and other planets but never gives too much away, even if Pandora itself was a little samey in terms of landscape and lacked population.
Ultimately though, Wing Commander would be the universe I'd jump to in a second. Life on the TCS Tiger's Claw would never be dull, or perhaps, even more excitingly, a tour of duty on The Midway to take on the latest threat to the galaxy after de-clawing the Kilrathi. That or the Warhammer 40k universe...anything with space or the unknown!!