I'll throw in another vote for intelligence being a group of abilities, which vary independently of one another. I think the only thing all of the abilities we call 'intelligence' have in common is this: they involve mounting complex adaptive responses to complex stimuli.
I'm a person that people meet and immediately label 'smart'. But although I can compose a sonnet in five minutes and kick anyone's butt at Scrabble, I'm no good at chess. In other words, I have unusually high verbal intelligence, but my abstract logical reasoning skills are average at best. Does that mean I appear smarter than I "really am"? Depends who you ask.
I think it's very hard to delineate a definition of intelligence that isn't a value judgement. In other words, whenever we stimulate someone and grade their response for its ingenuity, we're making a statement about what complex mental abilities we find valuable. This is going to vary considerably between different groups of people, depending on what abilities they've found indispensable for their group's wellbeing and survival. There are some cultural and professional circles where someone who is extremely sharp at picking up and reading subtle facial movements in other people is considered the brightest, because this skill translates into success within that group. There are others where having the ability to learn and execute complicated, demanding motor skills very easily is a mark of mental prowess.
I refuse to take an IQ test, because I don't feel I have to prove what an IQ test proves. I believe on principle in recognizing the high-level abilities each of us possesses, regardless of whether they're the ones the IQ test measures. I agree with those who say that IQ tests are culturally biased -- they test for those complex response abilities that the Western educational system, and educated Western society in general, deems valuable. An IQ test might give you a rough guideline to your chances of success in higher education (and jobs that make use of it) in the Western world, because it tells you that you possess the specific skills needed for this. The fallacy is to see the results of the IQ test as indicative of your global value as a sentient being, and the sum total of your ability to succeed at anything anywhere.
I think the most important ability for anyone to have is to realize that one's actions have consequences, and to consider those consequences in light of their effects on other people and the larger world. Anyone who can do this consistently is not a fool, as far as I'm concerned.