Though there is no distinction between importance of head-wanking and ethics based philosophies, if those head-wanking philosophies do answer legitimate questions as well, there is a distinction in what strand of philosophy they emerge from. The obvious way, for me at least, to distinguish these two strands is by referring one to philosophy, and the other to political philosophy. There may be problems with the terminology – that surely is not my fault – but these categorical distinctions seem to me pretty tight.

I also wonder whether we should be so quick to reject what you refer to as speculative philosophy (by which I assume you mean idealist philosophy, and metaphysics). I think that even though some philosophical issues and questions look like head-wanking, *good* philosophical inquiry is useful for the following reasons:
1) Conclusions we arrive at in ’speculative’ philosophy inform our reasoning about other, real-life concerns. So, for example, brains-in-vats thought experiments may give illuminating insights into, say, understanding the minds of others, and thus giving us useful things to consider when communicating thoughts to others.
2) Speculative moral or political philosophy may also give us normative aspirations. So, it is true that (using Nozick as an example) a particular theory of justice or the ideal society or the Good Life may serve little immediate purpose, but may indeed set a normative aspiration for politicians and individuals. The influence of Hayek (and Nozick) on the new right, for example, is pretty evident I think.
3) Also, do you not think that some useless-seeming thought experiments and philosophical bodies of thought, may serve to test the implications of believing something? In other words, because we act on our beliefs, and desire clarity in our beliefs, it seems useful to me to test the implications of beliefs through such speculative philosophising.
4) Even philosophers I’m not crazy about (Hegel and Heidegger for example — I’m not keen on either their ideas or their philosophic methods), though their philosophy may not ultimately be getting at any practical ‘truth’, give us useful ways of looking at the world. I’m a metaphysical nihilist and think that in the absence of any real metaphysical ‘things’ we’re at a most disheartening dead end when it comes to making sense of experience. As such, certain fictions and asbtractions may give us some guidance in terms of how best to make sense of an otherwise inchoate mass of data and experience. In this respect, speculative philosophy has the effect of organising experience and data into usably coherent entities. Even if it is just stuff of the mind.

Yet I do share your suspicion of some kinds of philosophising: much of what is labelled philosophy is of questionable worth as a contribution to reason-based inquiry. I’m generally spusicious of the extravagant theories-of-everything (and anything!) that continental philosophy tends to aspire to (ok that’s an exaggeration and maybe a caraicature of Cont. Phil., but I hope you get my drift). I hope I haven’t misstated your position in making these observations.

Philosophy proper is not a slur, I just mean it as the discipline in-itself, not one of many of its derivatives, such as political philosophy.

How does the fact that some philosophy is too speculative to be called political philosophy entail that political philosophy isn’t proper philosophy? I’m confused.

Owen, really now, there is philosophy that is too speculative to be called politically committed.

And I wish you’d told me you were’t being entirely serious, I’ve changed the locks on the doors now…