Bill M.

The very best genealogy site, hands down. FamilySearch is the one that the others cite as a source. If you're serious about genealogy this is a must. Best of all - IT'S FREE.

As far as paid genealogy sites go, MyHeritage is probably the best. The graphical interface is excellent and the matching is often quite useful. The downside is the same as for other commercial sites - basically your ancestors are being held for ransom. Communication with users is restricted to those with paid subscriptions so, if you want to interact with others, MyHeritage is probably not where you want to be.
Overall, it is a good place to conduct research. Some of the free sites (Wikitree comes to mind) are good places to post the finished product but are not conducive to actually DOING genealogy.