Like everything in Poker, the best starting hand depends. What type game are you playing? Limit, No Limit or a Tournament. What are the stakes? What is the texture of the game? How well do you play? Most important, what is your position?
Obviously American Airlines (AA) is the best possible starting hand, but how good it is depends upon how many opponents you are facing. Against one opponent a pair of Aces will win about 85 percent of the time. Against five opponents it will win only about 18 percent of the time.
If you are playing limit Poker and the stakes are less than $10-20, play, ABC, book poker. David Sklansky and Mason Malmuth have written excellent books that rank hands into five categories. They also have good basic playing strategies.
If you are playing limit, $10-20 and higher, no limit or Tournaments things are more complicated.
What is the texture of the game? Is it loose passive, where players rarely raise before the flop and four or five players are in to see the flop? Is it tight aggressive, where the first player to enter the pot raises and gets only one, two or no callers? Or is the table full of maniacs who raise often and several players will put in four bets to see the flop? Each of these games requires different starting hands, but in general Hold-em favors big cards over small ones.
How well do you play? If you are an excellent player, who can control the game, read your opponents, and use a number of strategies you can play more hands than an inferior player.
In Hold-em position is probably the most important consideration. There are three categories of position. If you are under the gun, one of the first three players to act, you need really good hands. If you are in middle position and no one has voluntarily entered the pot you can loosen up your requirements. In late position, if no one has entered the pot, you can play just about any two cards, raise and hope to steal the blinds. If you get called, especially by one of the blinds, you can still steal the pot. Most of the time when there are two players, the flop misses both of them. When that happens and your opponent checks, bet, he will probably fold. In a higher limit, no limit, or tournaments, stealing the blinds is important.
The best way to determine the value of your hand is through experience. Read some books to learn the basics, then play a lot of low limits to hone your skills. As you improve your play, advance to higher limits, and no limit. In learning no limit, tournaments are a good way to get experience. You only risk the buy in, a dollar to ten grand, and if you are good and/or lucky the payoff can be large.
To play good poker is like that old joke, "How do you get to Carnegie Hall? Practice, Practice, Practice."