I honestly believe that a parent's job is to raise their kids then set them loose upon society. Once they graduate high school, they should have the tools to suceed.
After that, the parent has to let them live their lives. Talk to them and be supportive, but don't intervene anymore, financially or any other way. They're going to have hard times and they might even fail, but a parent has to let them work their way out of it.
An important note is that there are times when it is okay to intervene, financially or otherwise. A child can sometimes go out and get into some pretty serious trouble. An abusive spouse or other bad situation can be difficult to overcome. In that instance, rescue them, get them back on their feet, but let them give life another shot. Don't try to hide them from the world, it won't work.
I'd like to add that my financial tap only has a drip coming out of it. *laughing* My wife and I have already told the kids they need to figure out how to make it on their own . . . oh, and if they do become successful, they are more than welcome to move us into their mansion. :D