Disposable magic items were always a moral dilemma for me. Investing in something that's single-use leaves you really intent on getting your money's worth out of that one usage. A scroll, for instance, can cost you a pretty penny but holds a spell you can only cast once. Thus, it's not uncommon (in my experience, anyway) to hold onto the item indefinitely, always convincing yourself that it's being saved for when you really need it. Even when you do really need it, you'll save it for when you really, really need it. In such a case, it ends up being wasted money. Most players are more comfortable buying a ring or a +1 weapon or some other item with a permanent and tangible benefit.
Wands are the beginnings of a compromise in that direction. With 50 uses before they're spent, they have a large enough store that players are usually comfortable spending charges when they're needed. However, 50 is indeed a finite number, and for wands that aren't holding severely specific spells, one that is liable to run out eventually. Until you've used all 50 of those charges, you haven't actually gotten your money's worth out of the item - and yet after you have used all 50, you no longer have anything to show for your spent gold!
So what's the real solution? Is there a way to comfortably spend money on an item that isn't yet another +1 to something on your character sheet? Can one make appropriate use of an activated item and still have something to show for it one or twenty levels later? Surely there's a way to take the utility of a wand and stretch it out a bit, isn't there?