There are a number of great restaurants in Portland, but there are lots of great places in wine Country as well. Here's my run-down:
Newberg
The Painted Lady - I haven't eaten here yet, but everyone tells me that it is great.
The French Bear - a great casual place and very good place for lunch.
Dundee
Dundee Bistro - Owned by the Ponzi family. It's a great place for lunch - a chance to see lots of winemakers. There are better choices for dinner.
Tina's - One of my favorite places. Great wine list, great food.
Red Hills Restaurant - Great wine list, great food.
Dayton
Joel Palmer House - Famous for mushrooms (including dessert

)
McMinnville
Nick's Italian Cafe - This was the first wine-oriented place in the Valley. Five course dinner. Everything is fabulous (especially the minestrone soup), but the main course can be uneven. Figure at least three hours for dinner.
Bistro Maison - Nicely appointed, good wine list, great food.
If I had two nights, I'd go to the Painted Lady and Tina's. If I had three nights, I'd add either Nick's or Red Hills.