The Town of Como is located in the southern end of the lake and given it has a direct train connection to Milan it is also the most likely entry point for most people coming to visit Lake Como.
The town itself offers plenty of good restaurants (which I recommend you book in advance!) and is also a nice place to spend a day walking in the small alleys and sitting in the cafes at one of the many squares.
The most famous sight in Como is the Duomo which for a relatively small town is pretty impressive. But of course nothing compared to the great Duomo in Milan.