You can pay for your license tabs online with a credit card and they mail them to you! no waiting in line! (actually, this is for all of Washington, not just Seattle)
$191.75 for a year, for a 7 year old car. $105 of which is for the Seattle Monorail, which isn't built yet and won't be done til 2009. And I had to go get an emissions test for the 2nd time in 3 years, at the cost of another $15 plus waiting in line for 20 minutes with my car running.
Pro I didn't realize until I looked at the Monorail page to see when the damn thing was supposed to be built by:
Monorail tax is deductible if you itemize. I did not know that, and missed it last year.