Robert Jordan's Wheel of Time series and Terry Brook's Shannara series. Both have more than enough material to work with and are particularly suited to conversion to TV. I'd also like to see something based off of L. Neil Smith's Probability Broach. With all the CSI type shows out there, a sci-fi gumshoe/alternate reality thing just might play well.
I'd pay not to see WoT or "Shannara" on film.
Tad Williams' "Otherland", but it's too long to be anything but a series.
Keith Laumer's "Retief" stories would be a great tv show...