I like NZBsRUs. They do have a download limit(unless you pay), but if you just download the NZB's off their IRC channel then there's no limit.
I prefer it because it's a nice clean site, and I like browsing by categories. Which is why I use it more than a search engine like Newzleech.
There's a lot more too. I think in a topic a page or two back is devoted to naming a bunch of these forums. Just search for it.
