[Taqwus]

You can wish for any monster or any magic item, including those which cannot be forged and artifacts which already exist.
You can also wish for Armageddon. "Magic power" is another nice one, especially if you already have a ring of wizardry; it gives +1 on all eight magic paths up to a base of 10. ('regular' power wishes -- +50 hp, +20 str, +10 att, +10 def, +10 prec, non-cumulative; hp bonus is affected by GoH).
If you're starving, you could wish for supplies; if you need militia, you can wish for that.