O Arquinho do Castelo

A very good restaurant mainly dedicated to seafood. The octopus is very good.

It is situated in Matosinhos area. Here you can find many other good restaurants.

Location/Contact of Arquinho (not at walking distance so you should take a taxi or bus).

Adega Presuntaria Transmontana

A restaurant with typical Portuguese food of hams, chouriços, octopus and other (not very cholesterol friendly) tasty dishes. The dishes are mainly "tasting" size and not main dishes. But if you are able try everything you'll probably win some prize.

A good place to go with friends and share the different dishes.

It is on Cais de Gaia (other side of the river). See here for location/contact and NYTimes review.

Praia do Ourigo

Bar Praia do Ourigo is a very beautiful restaurant. The view is to the spectacular Foz do Douro. You can have a meal or just go for a cup of coffee. In either case, you'll enjoy a very peaceful time.

It is located in Esplanada do Castelo, Praia do Ourigo in Foz do Douro (that is to say here).

(review from the NYTimes)

(photo is from traveldo)

Vegetarian Restaurants in Porto

A few suggestions:

• Nakité Produtos Naturais Lda
• Maria da Graça Vaz da Silva Sociedade Unipessoal Lda
• Vegetarian Restaurant O Verde

Bridge D. Luís / Cais de Gaia

One of the best ways to enjoy a magnificent view of Porto and Ribeira, and to get in touch with part of the history of the city, is to walk across bridge D. Luís. On the right of it, if you're facing Gaia, you can see the remains of Ponte Pênsil, an old bridge that was to replace the one that collapsed in an event of the Napoleonic invasion (it was made out of wooden "barcas", which are small boats). There is a panel on the other side of the street that still has candles burning to mark the event. Oh, by the way, Napoleon couldn't conquer us :-)

When you arrive at the Gaia side, you can enjoy an amazing view of Ribeira, have some Port wine, and there are some restaurants with that fabulous view as well, in the "Cais de Gaia". It's impossible not to spot it!

Wikipedia has a nice summary on the history of Porto.

Cais de gaia has a website with a list of restaurants and activities.

"Café Âncora d'Ouro", a.k.a. "O Piolho"

"O Piolho" is one of the favorite meeting places of Portuguese Students (usually after 10pm). Of course you can also eat a good "francesinha" there!

Location here

Best restaurant for "Bacalhau com natas"

The best place in Porto for a very traditional (and delicious!) Bacalhau dish, which is "Bacalhau com natas" is the

Restaurante o Lavrador

Rua Brito Capelo, 14 - 16

Porto

Wikipedia entry for "Bacalhau"

Capa Negra 2

A fine (and afordable) restaurant for some of the best Francesinhas and Rissóis in town:

Capa Negra 2

Localization here.

In case this is full (it happens) there is another very good restaurant right up the street: Shakesbeer. Localization is available here.

Restaurants - Zé Bota and Papagaio

After the more expensive restaurant, here go the affordable places.

Traditional portuguese food in affordable restaurants in the center of Porto (by Leões):

Restaurant Zé Bota

Travessa do Carmo 16/20, Porto

Restaurant Papagaio

is right by Zé Bota.

Restaurant - Portucale

One of the best restaurants in Porto, with an amazing view over the city:

Portucale

It can be a bit "heavy" on the wallet, depending on what you order, so beware :-) Worth every penny though.

Restaurant and Bar in Ribeira

My favourite places in Ribeira:

Restaurant:

Casa Filha da Mãe Preta 

Bar:

Prioridade

Rua da Lada, 76-78

Porto