Sure.
There's a great place for Breakfast in Palermo. It's French but if you want decent breakfast (eggs (scrambled and benedict), waffles, bagels, etc.) you should give it a try, On weekends they serve "brunch" which is not the kind of brunch I'm used to but it gives you expanded options. They also have killer lemonade. Oui Oui is the name, it's on Nicaragua (corner of Arevalo, Dorrego, I guess).
The place that serves American style food (they also serve other things like tapas and pasta for some reason) is a place in Puerto Madero called Unico. It's quite unique, the mix is quite something (the name is quite appropriate). It feels a little like TGI Friday's, it's open late and it's also a bar. Their portions are huge and the service is great.
I could recommend other things but off the top of my head those two deserve a special mention.