I will probably dip into all my past modules and reuse some of them for conan. i like a bit more of the 'weird' in my conan game definately not pure REH, more of a conan/cthulhu/thieves world/lankmahr mix would be the closest.
i planned on using the slaver's series as well sometime down the road
what else would be good
ravenloft touch of death
against the giants (thoughts of using this as one of the remaining outposts of the giant-kings, no drow though or even multiple giant types)
dwellers o/t forbidden city
hidden shrine of tamochan
sinister secret of saltmarsh
final enemy
danger at dunwater
cult of the reptile god
temple of elemental evil (parts of this could be used)
isle of the ape
keep on the borderlands
lost caverns of tsojcanth
forgotten temple of tharizdun
the lankmahr stuff
newer stuff i've been thinking about is gygax's necropolis, green ronin's freeport series i think would fit well into a pirate game, a couple of the kalamar modules could be adapted well.
it all really depends on how much work you want to do in converting like i said i want a bit more of the weird element in my games. that doesn't mean i want fireballs, magic missiles, ready cures, or a bunch of magical items, but if it's snake men, giant-kings, things that make you think lovecraft then i'm all over it.
i'm the type of dm who sets down and figures out what i want to do w/ the players put together a rough outline and go.....i tend to do a lot of fly-by-the-seat-of-my pants dming, and honestly those games i do like that are typically a lot more entertaining than one i've done hours of prep work, b/c envariably my players go off in another direction and i've wasted a few hours i could've been doing something else with. so i won't spend a lot of time worrying over the details if i use any of those things. i'll have an idea what i want to replace, have some handy npc stats close by and wing it
