Montevideo is a typical south-american city, with huge contrasts all over the place and lots of historic building to be seen. Be aware: the food is rather expensive!
Favourite spots:
I really enjoyed seeing Plaza del entrevero at night.
What's really great:
You can have a great history lesson just by walking on the historical streets and by seeing the monuments.
Sights:
Plaza del Entrevero
Other recommendations:
I don't really remember, as it has been 6 years since I've been there...just keep you distance from parrilladas (famous dish).