In response to declining sales (a 21.3% decline in the most recent quarter), Buell[1] will be discontinued:

"Harley-Davidson also unveiled major elements of its go-forward business strategy to drive growth through a single-minded focus of efforts and resources on the unique strengths of the Harley-Davidson brand, and to enhance productivity and profitability through continuous improvement. As approved yesterday by Harley-Davidson's Board of Directors, the Company will discontinue its Buell product line and divest its MV Agusta unit as part of this strategy."[3]

Read more about it here[2].

[1] http://www.buell.com/
[2] http://www.motorcyclecruiser.com/newsandupdates/0910_crup_harley_shutter...
[3] http://www.harley-davidson.com/wcm/Content/Pages/HD_News/Company/newsart...