Renting a car is only a good idea if you wanna visit different cities and most of them are too far away (15-20h drives).. If i were you i'd take an omnibus to go back and forth from BA -- Rosario -- BA. Those are cheap and very comfortable. So you'll probably land in EZEIZA. The bus terminal is in retiro. Tickets can be bought online but also there. Be carefull for pickpockets in that area. It's located next to one of the biggest villas miserias (slums) of S-America.
http://www.omnilineas.com/argentina/bus/retiro/rosario/
Driving a car in BA is pure madness and you'll be better of taking taxi's exploring the city.
Things to do in Rosario. I heard the going-out scene is pretty good there, so you might wanna go clubbing one night there
Things to do in BA
- visit the different neighbourhoods: Recoleta, Microcentro, Palermo, Puerto Madero, La Boca which are the most memorable ones.. Be carefull in Boca and def with taxidrivers who scam you with their payment meters.. They know it's mostly tourists going there.
- go to some of the finer restauratns for great cuisine or a delicious steak
some recommendations:
look them up here for adress/type of cuisine:
http://www.guiaoleo.com.ar/
La cabrera (steak), green bamboo, oviedo, Tó, Osaka (best sushi/french-oriental fusion restaurant i've ever been to),
- clubbing (crobar/pacha are decent)
- they have quite some nice museums (like the national art museum)
- check out rosedal park + jardin japones (japanese garden)
Not really coherent but I'm sure guys will chime in and help you out.
Join our facebook group SHIP IT BUENOS AIRES, there are enough guys here and they will probably take you around, so you can ask there as well since some don't read 2+2 topics anymore