Is poker gambling?

[JackSevenSuited]

The other day me and my friend were arguing about the very nature of poker. Is poker gambling? I know in a literal sense putting money into a community pot, whether in blackjack, roulette or poker is risking your money, therefore gambling, but theoretically Is poker really a gamble. Assume you only put money in the pot when you are a favorite or getting the right price due to skill (knowing your opponent, pot odds etc). In terms of the math, you can expect to win more than you lose, making putting that money into the pot an investment rather than a gamble. I know luck gets thrown into the mix but theoretically the luck will even out over the long run. Suggestions, comments?