Yesterday, I visited Valparaiso and Vina del Mar from Santiago in Chile.
On the bus, a local lady from Valparaiso kindly gave me information about Valparaiso.
I asked for a good seafood restaurant. And she recommended me Bar La Playa. It was a very good and unique place. People there were very nice. The waitress was very kind. She even let me go behind the counter and took a picture for me. It is not listed in South American Handbook - the guidebook I'm using. The price range is the middle range in that book, i.e. $6-11. Good food. It's located just west of Plaza Sotomayor. There is an entrance both on Cochrane and Serrano.
Speaking of what's new from the information on the guidebook, the train between Valparaiso and Vina del Mar is actually a modern Metro. You have to purchase a card for 500 pesos. Then you have to add money for the fair on the top of it.
Entrance of Bar La Playa on Cochrane (Avenue?) in Valparaiso
Vina del Mar