Half of the goalies taken in the first round end up not contributing at a level higher than a backup goaltender. Furthermore, many of the goalies that do go on to have success do so on other teams (Luongo, Giguere). Even the goalies that "work out" are often not the best goalies drafted. Of the goalies that received more than 15 points only 5 out of 14 were drafted in the first round (the others not already mentioned are Turco, Nabokov, Theodore, Potvin, Carey, Osgood, Salo, Khabibulin and Turek) and that doesn't include goalies who came into the league without being drafted (like Curtis Joseph).
As Kent so eloquently stated in his article on this subject, the goaltending position is unique. Either you're one of the most important contributors on the ice or you're not playing at all. Far too often, goaltenders taken early in the draft aren't playing at all and teams are using a valuable asset (a first round pick) on what looks to be a coin flip where the most common payoff (a short term starting goaltender) is something that's readily available on the cheap during the summer. And it's not as though the situation is getting better. Marek Schwarz (17th overall) has yet to have an impressive AHL season. Devan Dubnyk (14th overall) hasn't been much better. Neither has Al Montoya (6th overall) and he's already on his second organization. Hannu Toivonen (29th overall) has burnt through two organizations and is now playing in Finland. In short, don't use your first round pick on a goaltender.