play as many as you are comfortable with, helps if you have played players before and know there style and ranges sng or cash........
I find pokeraceHUD the biggest help when i play 3 or more,once you get used to the stats and how to use them you"ll find it invaluable.
As for fun, if you open up 10 tables i can assure you , you will have fun
2 monitors help as well ....................