If you want a "chain" hotel, the InterContinental is available starting at $159/night next week on the pre-paid rate.
I've stayed there several times - I think it gets somewhat mixed reviews online but I really like it.
The area is somewhat quiet at night (a plus in my book) but it's handy to get around. A couple of blocks off 9 de Julio via Moreno which also has a subte station. Walkable to San Telmo.
Rooms are in a more classic decor than contemporary so it has that nice touch to it. Get a room overlooking the courtyard between the hotel and the curch next door.