Personally, I find that traversing data structures recursively is more straightforward than iterative approaches, at least for most of the data structures I deal with. This sort of thing, for example:

  (defun search (tree val)
     (cond
        ((null tree) nil)
        ((= (car tree) val) tree)
        ((< (car tree) val) (search (cadr tree) val))
        ((> (car tree) val) (search (cddr tree) val))
        )
     )

I write this sort of code all the time for more complicated structures; iterative solutions would involve keeping track of a bunch of local variables, which only makes the code more difficult to deal with.