seasnake
Conquistador
What about their unique unit? I'm about to buy the Inca-Spain pack, is it worth it?
Definitely, the Inca is great but don't forget Spain. Spain is a ton of fun to play, their UA forces you to explore the map seriously and chase down those natural wonders. Further, Conquistadores just rock, great for a second wave of settling on everything but a Pangea map. Spain is a lot of fun to play.
All of the DLC civs are actually really good in my opinion. Polynesia and Babylon are great if you haven't tried them yet.