A good objective statement tells a plainly-state title you would like ("UNIX programmer", "CGI Developer", "Project Manager", "Prostitute") and a couple skills that you have ("excellent writing skills", "experience with digital audio technology", "excellent oral skills", etc.). You can also specify what industry or department you want to be in ("financial services", "telecommunication", ".COM", etc.).
Here are some good ones that I've seen:
In that last example "expand" sets an expectation of being a little green at VB.NET, etc. Replace it with "utilize" if you want to set an expectation of already being an expert. Companies do hire both, so don't set unreasonable expectations.
A sample bad objective statement (this is a real example):
That person didn't get any calls back, even though he had built .COM infrastructures that served literally millions of users email, web services, etc. The person was quite brilliant with technical things, but didn't write a resume that would get past the clerk: It didn't include any buzzwords or technology that the clerk could recognize nor a tangible position/title that was open. How could the clerk classify such a resume? It has to get past the clerk to get to the hiring-manager.
A better statement would have been: "A senior architect of UNIX-based (Solaris, Linux) email and web services that lets me utilize my experience in building extremely scalable systems with high up-times." He did change his resume to something similar, and soon started getting phone calls.