Let's Clear This Up Once And For All
When I was in high school I used to routinely use i.e. instead of e.g. for the same reason I think most people do: They believe it sounds more scholarly. (Most people, myself included, do the same thing with "in lieu of" in lieu of "instead of," which is fine grammatically albeit equally pointless.)
The problem is that i.e. and e.g. mean two separate things, two completely different things. And when, during my freshman year in college, I learned what i.e. meant, I felt like a dolt for having misused it so often. I imagined hip socialite linguists chuckling to themselves as they overheard me trying to impress some broad at a party: "I like film noir, i.e. 'The Postman Always Rings Twice.'"
I was petrified, and quickly made sure to drop the habit and use i.e. appropriately from then on.
But this came as both a blessing and a curse. I was astounded at how often it was me who was doing the chuckling as some socially aspirant undergrad tried to impress a coed with his use of i.e.
Then, a shaft of light illuminated the tunnel of public misunderstanding. The movie "Get Shorty" addressed the i.e./e.g. conundrum and at last, I hoped, the abusers would realize their folly. Unfortunately, the movie was not as popular as I had imagined it would be. Wholesale misuse of i.e. continued and the movie now collects dust at video rental joints across the nation.
So I will reprise the explanation for your elucidation:
e.g. = exempli gratia — for example.
i.e. = id est — that is. (e.g. Kevin Spacey is an exemplary thespian, i.e. when he's not high on uppers.)
I usually don't get my panties in a bind over matters of grammar. Sure, I'll roll my eyes when people confuse "anxious" with "eager" or use "hopefully" as a sentence modifier, but I usually keep my trap shut until the grammar abuse is particularly bad.
As I see it, making a correct distinction between i.e. and e.g. is not being overly finicky. There is no debate among linguists as to the meaning of the two abbreviations (as there is with the etymology of "hopefully"). Therefore, no one should be able to argue that misusing either abbreviation is OK as long as the point gets across. With that line of reasoning, there is not much hope for the sanctity of grammar.