When I think about the times that I like to play, I have this picture in my mind of people starting to get off of work and arrive home on the east coast. From then until the time that the nine-to-fivers or the west coast start going to bed is what I think of as peak playing times for
online poker in the US. It may sound strange, but that is the time frame that I avoid playing in. I know most players think of this as the time when the most fish are swimming and would look to take advantage. And of course, this makes a lot of sense for cash game players.
I am more of a tournament player, myself. Also, as I've said on more than one occasion that I tend to do better against better players, as I find it easier to understand how they think and play. For that reason, I tend to concentrate my play in a timeframe between midnight and noon. Depending on my results for the night, the last tournament I will register for might be starting at about 9:30 or 10AM. I tend to do pretty well during this time period as the tournaments that I play in tend to have a good mix of skilled US players, a few fish thrown in and a sprinkling of European players. The tournaments tend to have large enough fields to generate decent prize pools but not so large as to make winning them seem like more of a crap shoot than a card game.