Yeah, IMO seti has really done nothing with all this power. They have been going for what 10 or 12 years? In the end, they are not likely to find anything of relevance to mankind.
There are other much more worthy projects, IBM's World Community Grid for example doing research on medical issues that really can benefit mankind.
http://www.worldcommunitygrid.org/
I do wonder though about the effectiveness of these home based grids. Surely the money spent managing and collating the data would be better spent on a proper supercomputer that would outstrip the grid in terms of achieved data, and use thousanths of the electrical power that all these PC's consume, adding to the greenhouse issue.
The efficiency of community grid computing must be attrocious.
Cheers,
Jason.