My apologies for inadvertently slipping into process theology language when I wrote, "In short, we should desire what God desires."
Okay, so saying that God "desires" something isn't exactly process theology. In fact, it's even Scriptural.
Still, I wonder if the impression it gives isn't a little too passive, as though God experiences a desire that subsequently causes Him to act in some way. There are a lot of problems such a theology raises, but I think the fundamental one is that, if God were like that (which is to say, like us), He could experience a desire that subsequently causes Him to break His covenant. Many or most of the Scriptural references to God as unchanging are in the context of His fidelity to His covenant, but if God could change His mind, then either He could change His mind about keeping His covenant -- contrary to Scripture -- or He could change His mind about some stuff but not about His covenant -- which is a tough proposition to make sense out of.
Anyway, if I say "we should desire what God wills," I avoid all this. It doesn't resolve the problem of whether what God wills always happens, of course, but it makes it clearer that such things as the damnation of the reprobate and the salvation of the blessed aren't simply things God wishes for or is hoping to achieve, but rather what God is acting to achieve (and, therefore, will achieve).
St. Thomas, by the way, takes a perversely Pollyannish view of what happens when God's will appears to be thwarted:
...that which seems to depart from the divine will in one order, returns into it in another order; as does the sinner, who by sin falls away from the divine will as much as lies in him, yet falls back into the order of that will, when by its justice he is punished.
After all, that God's will is always done should make us glad.