Hi sophiegirl -

I stay in Seattle regularly and have stayed at all 3 of these hotels. My comments:

Hyatt Bellevue - this is in the eastside, surrounded by shops and restaurants. It's a very nice hotel - one of the best in Bellevue. However if you are looking to stay in Seattle, this is a 20 minute drive with no traffic (and can sometimes be over an hour with traffic). However if you are looking to be away from Seattle, this is the place to be.

Hyatt Olive 8 - a smaller boutique-feeling hotel. It just opened in February and you can almost still smell the fresh paint in the rooms... The restaurant in the hotel is not open yet (that i know of), but they do have supposedly have a great spa. If you're into spas it might be worth checking out. The Olive 8 and the Grand Hyatt are right next to each other, so neither has an advantage. They are on the north side of the city, away from true downtown. It would be about a 10 minute walk to Pike's Place market from either of these hotels.

Grand Hyatt - if you're looking for something more grandiously luxurious, the Grand Hyatt is the place. It has bigger rooms than the Olive 8 and a Ruth's Chris steak house attached. The place is a bit more expensive than the Olive, but in my opinion worth it. I've been upgraded to a corner room twice there (no status with Hyatt), so upgrades are easy to come by. If you don't care about the spa and have a few extra bucks to burn, go with the Grand Hyatt.