I love "Texas Hold Em" by Ken Warren. It was the first book I ever read about poker and I still go back and read parts of it today. TJ's book Champion no-limit and Pot limit is also great. Haven't read Supersytem yet, but hear great things about it.
I think Helmuth's books says to play .50-$1 tables with a $100 bankroll for online limit hold 'em. But it all depends on the player, experience, etc. I think.