As things currently stand, there will definitely be no new roller coaster next year, and most likely no major new attraction either.
ATA has learnt that the rumoured water ride for next year is based on rough future plans drawn up some time ago, which have since changed. Although the park have not ruled out ever installing a new water ride (bear in mind the park's future plans change week-by-week), they have confirmed that there will be no major new ride for 2007.
However, you will be pleased to hear that 2008 is currently planned to be a really good year for Alton Towers in terms of rides - read into that what you will! With the theme park's budget for 2006 to 2010 set at £30 million, that certainly could mean a new roller coaster.
Fans of the park hoping for a wooden roller coaster shouldn't get their hopes up, sadly - there are no plans to install that any time soon either.