I find it irritating that so much of the (massive) media attention on wikipedia right now hinges on a false dichotomy: whether it will (a) render the Encyclopedia Britannica obselete; or (b) implode. Reasonably, the question is not whether wikipedia will succeed, but the extent to which it will succeed.
I predict that within a year, (a) Wikipedia will have adopted a /. or ebay style reputation system; (b) the scope of changes that a user may make will be, to some extent, limited by his reputation level; and (c) anonymous users will be either banned from edits or severely limited.
These changes would, while not solving all problems, solve most of the problems that have been identified to date.