Tear down this viaduct
The governor says that no action is not an option - and she's right. That is why it is time to move forward, demolish the viaduct, and shift most of the money set aside for its replacement to the State Route 520 floating bridge project, which is no less deserving of the funds (in fact, it's probably more deserving since its loss would be more devastating to the Seattle metro area).
The city's leaders are completely opposed to a new viaduct for a number of reasons, while the state's leaders are opposed to a tunnel (mostly because of the cost hurdle, which Mayor Nickels has largely failed to overcome).
We have supported a tunnel and we will still support a tunnel if funding can be found to pay for it. But there doesn't appear to be enough. It's time to give very serious consideration to the option the governor and WSDOT don't seem interested in thinking about - a surface/transit option.
With light rail arriving in 2009, and with a good mitigation plan, Seattle might be able to cope just fine without a free-moving Highway 99 along its central waterfront.
It's time to put plans in motion to remove the Alaskan Way Viaduct before Mother Nature decides to remove it for us at a far greater expense - and allow the State Route 520 program the opportunity to jump ahead.
UPDATE: Erica Barnett has excellent analysis of this over at SLOG.