Is CPU mining even worth it?
For the amount of time you would spend setting up a CPU miner, at minimum wage in the US you would be at a loss.

Even GPU mining is barely profitable for most people right now. It would definitely be more profitable to speculate, and even more profitable to operate a Bitcoin business. There are a great deal of people who want to use their Bitcoins for purchases.

At the current exchange of under $10:1BTC, the most efficient graphics cards are taking months to pay off their initial investment (with free electricity).