We really enjoyed going to the penguin rookeries, both in Chile and Aegentina. The down side of these two tours is getting to them by bus and/or ferry. (Getting there was a real drag.) You should at least go to one of the rookeries. We preferred the one on the Chile side.
In Ushuaia we took a boat/bus tour of the national park. It offered beautiful views of many species of animals and the Andes mountains.
The park is really beautiful.
In Puntarenas we did a private tour of the waterfalls and glaciers. The cost was reasonable and it was far better than being in a bus all day.
The highlight of the trip was the "Senor Tango" tango show and dinner in B.A. The show is fantastic. The theater is beautiful and the food is quite good with free wine as well. The evening begins at about 8P.M. and ends at around midnight. Don't let the name "Senor Tango" fool you. This is the best tango show in town.
The cost was less than $50 p.p. including transportation to and fro, leaving from the pier. You can make reservations on the street just outside the terminal building where you check in for the cruise.
I hope this helps. Feel free to e-mail me if you have further questions.