It's great for placing an ancestor. Since I pretty much have all but 2 of my gg grandparents in the census records back to early 1800s I now use it mostly to track down siblings of my direct lines. This has sometimes led to more papertrails from my own direct line when they are listed in records of an area where their siblings lived.
This site is really growing. Wish they had more TN records but I was so excited to find some of my TN relatives that moved to Huntsville AL in the AL death records which they recently added. They also have a good bit for my husbands Michigan lines.
Hugh Wallis' IGI Site
While I've used it mainly for the US sites I need to explore the Canadian ones for my husband's lines.
Every link to be had for just about any surname or place. If it ain't here then it's just not out there yet.
Facebook is wonderful for keeping up with my Genealogy contacts and also with my family.
This is the one site that I did subscribe to this year. I love it but wish there were more offerings for those researching in the Tennessee area.
I've always loved the RW Genealogy Mailing lists and they are even more useful with their current search capabilities.
Joe Beine's Death Index Site
The TN page of this site brings many of the sites I'd list seperately were it not for them being brought together there on the TN page