Basement yes, usable no. There are a couple issues with it. First, our furnace is the size of a buick roadmaster, it's from 1953, but still works perfectly so no need to replace it. Between that, the washer/dryer, hot water heater and the giant root cellar cut out of it, there isn't a huge amount of space down there. Secondly, it's only a 6 foot ceiling, me being 6'1" makes spending any real amount of time down there uncomfortable. Finally, if we get heavy rainstorms, there have been instances where the french drain doesn't really keep up, so water could be an issue.
Attic doesn't work either (low ceilings), not that I'd want to cart something like that up all those stairs anyway.