Yeah, as mentioned here already, there are a whole bunch of threads on the topic.
I like
WSN Links. I am developing a site with it now. WSN is full featured with the following warnings:
1. You need to know HTML to customize it. It is highly likely you'll want to do this.
2. Support is good but the owner is a crusty bugger and does not "suffer fools gladly".
A single domain license it now $99.
---art