The answer to this is all over the Forum, so you best read up on the first page. If you insist on being a tad lazy, here is the answer in a nutshell:
- speed: weapon speeds 2.6 seconds or slower
- reason: faster speeds lose windfury procs due to the hidden cooldown on windfury of 3 seconds
Now go read up! (elitistjerks.com is a good site too)
Oh yeah, and welcome to the hellhole. /cheer