Through March 2010, it was seen that most of the parked pages, even if they were keyword rich domain names, have slowly vanished from the search engines.
Just a month back, in February, many parked pages (of well known networks) were found even on the 1st ten SERPs, but not anymore. So, dear entrepreneurs, please spare time for your well thought out business (domain) names and go the development route. At the very least, set up a one page blog and just jot down some notes about the topic that the business name represents.
Update: July 14, 2010 – An interesting take on parking by Howard Neu.