Welcome aBoard, reebecca--good to have you. Good question, indeed. jheem, I was glad to see your expansions on your first statement, because I had misinterpreted it entirely.
I would agree that intellectual is more pejorative, but I would also say that it is considered pejorative because a large part of society uses it that way. (I for one don't.) It seems to be equated with terms such as "square", "nerd",
"snob", and at best, "pretentious".

As to the distinction between say an intelligent person and an intellectual person --that's a tricky one! I don't agree that "intelligence" necessarily always includes common sense, or that the implied opposite, intellectuals don't have common sense, is true. But maybe others have seen the words used in these circumstances. I haven't. If I had to get right down to it, I think I would go with (and I believe this fits wsieber's metaphor) saying that a person might be considered intellectual based on acquired knowledge--what they say, and that someone might be considered intelligent based more on what they do--how they act on knowledge/information, pre-acquired or just-learned. Augh, no--I take it back! I've heard people being described as intelligent who demonstrate by their verbal expressions lots of acquired knowledge! Maybe it's more that a person is considered an intellectual if they demonstrate knowledge that is more esoteric (in one area or more) than most peoples'.

Hmm--where would this instance fit? (And it doesn't necessarily have to be either of the above!) One day many years ago, I noticed at breakfast that I was out of milk. Later in the day I heard a report that we would get a heavy snowfall overnight. It took me till evening to put the two pieces of information together: that hey, it would be a lot easier if I went to the grocery this evening before the snow fell. So I did. What can I say? I was young, and hadn't been out on my own all that long.