You might want to check out the carpet blades at Harbor Freight. A lot of folks here swear by them and they are really cheap.
http://www.harborfreight.com/pack-of...des-97642.html[/quote]
I bought lots of em and they are much sharper than the expensive ones from LQS! I used one for months without having to change it, I was shocked that it lasted so long. And it cut 'like buttah'