Yes, because a) it means not so many people will be disenfranchised by living in a safe seat; b) it allows you to express your nuanced opinion in a nuanced way (I've never found myself in complete agreement with any candidate); c) coalition government as a system shouldn't be judged by the current shower - it can be effective, and is a fair(er) reflection of the people's will (which is what democracy is meant to achieve). Yes, there will be horsetrading, but tactical voting is horsetrading too.

The downside is that it will please Nick Clegg.