These are smart recommendations. One quibble is that I consider Corson Building--or its sister place Sitka and Spruce--more "Seattle" than Lark, which IMO has trended away from a creative seasonal local menu. Note that it's a communal dining experience at Corson, which may or may not be more "quintessential" (or agreeable to you).
Don't think a Tom Douglas dinner makes the cut for 36 hours, but you could hit up Snackbar for lunch. Spinasse > Barolo, but a New Yorker has Italian galore; curious that the NYT recommended that.
There is lot of recent hype and love over Walrus & Carpenter too, and slurping puget sound oysters is essential for your visit, but those may be on offer at one or more places on Sam's list, and certainly makes for a good pre-dinner session whever one can find the bivalves. Inquire locally.
Actually, I neglected to put Sitka and Spruce on my list, which I heartily recommend -- and it is, indeed, quintessential Seattle. The only reason I wouldn't put Corson on that list is that's it's a little high end to be considered "quintessential." But we're splitting hairs here.
The NY Times answers this exact question earlier this week in an article likewise titled "36 hours in Seattle": http://www.nytimes.com/2011/03/27/travel/27hours-seattle.html?_r=1
Overall, pretty solid reccomendations with the exception of Barolo - I think you could do better at Spinasse or Volterra for Italian.
Looks like the times likes to hit this topic every two years or so:
2008 version: http://travel.nytimes.com/2008/11/23/travel/23hours.html
2006 version: http://travel.nytimes.com/2006/08/04/...
Seattle, WA, Seattle, WA
1940 Westlake Avenue, Seattle, WA 98101
5411 Ballard Avenue NW, Seattle, WA 98107