S'fair enough:) Though I wasn't suggesting that recursion itself was non-useful. I agree that there are many algorithms which are naturally recursive and are much easier to both think of and implement using recursion. Almost anything to do with trees is a good example, but in all the cases I can think of where this is so, retaining state at intermediate points in the repetition is an integral part of the algorithm. Ie. Intrinsic to the delivery of the immediate final result. As opposed to a potential, future final result as can be delivered using the memoize case you cite.

I've not had the occasion to use Memoize in anger, but I read some of Dominus' arguments for it and Streams and stuff, and it is certainly a neat way of speeding up existing code (amongst other uses), but I was struck that it would be cheaper in memory and quicker to just re-code the original function to use a lookup table, though I can see this doesn't have the infinite list feature, but then I don't have infinite memory either:).

I very definately agree that dismissing any better screwdriver out-of-hand is silly. I was just hoping I might get some good counterpoints to the tail-recursion-is-a-hack -elevated-to-goodness argument that I was pretty much convinced by several years ago.