Upon further reflection, I might support tearing down the viaducts if we get a ferris wheel out of it..
Transportation aside, like Locked In posted above, the viaducts and the area around them are an interesting place that is unique for the city. I really like the space that they create, even if it doesn't necessarily 'jive' with what most of us consider to be Vancouver from down there. But hell, from up top, it provides for some amazing views of False Creek. When heading home from downtown, I love to look out at False Creek and Science World.
I'll agree that we don't need the full capacity that the viaducts are currently providing, however, without them or with ground level roads in their place, we would have some really nasty congestion issues to deal with. Hastings is pretty congested all day long - it's not just during rush hour. I agree that we need to put more money into non-car infrastructure (rail, cycling paths, SkyTrain), but
this should not be at the expense of those that choose to, or need to travel by car! Once access to transit in the region is improved (new ALRT lines/expansions, all day WCE service, streetcar), I can understand considering something like this, but not until we start seeing a natural shift away from private vehicles. Given our geography, this just doesn't make sense right now, especially for the pocket change that the CoV would gain from this endeavour.
I'll also agree that the viaducts provide some disincentive towards development, but it's not the end of the world as shown by deasine's concept. The NEFC can and will be developed eventually, with or without the viaducts in place. All things considered, I think that it would be silly to tear the viaducts down now or in the near future. Once they reach the end of the lifespan, we may not want to replace them, but we need to consider all the facts rather than just get behind the 'cars are evil' mantra.