Ravelry is fabulous, but more as a tool IMO. The forums don't compare to KH. Maybe it's because there are so many and the whole system is huge.
I use Ravelry all the time to search pattern and yarns. You can also find a yarn you have in your stash and see what others have made with it. Or find a pattern you like and see what yarns people used to make it. It's a great resource for that kind of thing. It's also nice to keep track of your projects.