Then your chances are better, but it's still tough to say. Try using Instantwatcher.com to see if what you want is there. It tells you whether HD is available.
VUDU has purportedly the most content in HD, and a fair mix of new and old. It's pay as you go, no fees to sign up. Its prices are higher than most (up to $6), but they give you a free movie rental to sign up, have lots of 99 cent and $2 deals, and are a good way to supplement Netflix.
Amazon also carries streaming. If you're a Prime member, it's included.
Don't believe everything on the Interwebz! A duck's quack DOES echo!