If you want the absolute best pizza and beer, piecora's at 15th and Madison. If you like Italian, I like the spighetti factory, I think it is first and broad, right down the street from seattle center, or up the street from Elliot bay.
I love the underground tour and never had sexual overtones, I brought my kids with me. The city pass is okay, but I would rather do things a little my way. I like the air museum, seattle center but I also love the monorail and the silence center which is not on there so I would not get it. If you do you can do many of those things in a single morning. The aquarium only takes about 2 hours, the space needle would need no more than 1 1/2 hours if that, when at space needle you are at seattle center, nice to walk and may be several things going on, if not wont take you more than an hour, that is also where the science center and the monorail is, and also EMP, not a big fan did not care for jimmy Hendrix or cobane, but if you go there you could do all of that in one day, maybe a bit fast but none are that big that you would need a whole day, except if something is going on at the center that interest you.
Others gave you the seafood places. I could keep naming, but I think you have enough for tourism. I lived Tacoma for years, moved away and just moved back to capital hill seattle. Home will always be Boston but seattle is a great place also.