Bump! Let's keep this one active!
I'm a first generation college graduate and I think there are definitely hurdles we face that others do not.
First, there are--undoubtedly--family issues. My mom kept telling her friends (and sisters) that I was getting an AA in Sociology and that I would graduate and then get a BA. It was cute, at first, but then it was confusing... Especially when she crossed out "BA" on my graduation invitations, thinking I had made a typo. And as supportive as she is, she and other members of my family think I'm an elitist--they think I think I'm better than them. It's stupid family drama, I know, and we all love each other... but it makes the holidays a little harder every year.
Second, there are--undoubtedly--class issues that change your college experience. Working a full-time job and trying to be a full-time student with extracurricular activities is trying. My senior year of undergrad, I switched to a part-time job in order to get my GPA up to a 2.85 (which I managed to do). My boss offered to pay for me to take the GRE and I cried at work that day. I read (especially on this forum) about folks who take the GRE multiple times and I cringe a little. Even taking it twice would keep me from paying the rent. And people without these experiences will ask, "Well, just because you don't have money doesn't mean you can't do well in school. It's your own fault." And I'll admit that I could have gotten better grades, but I also ask them to kindly imagine having to walk 2 miles to school five days a week because your loser boyfriend disappeared or was got drunk after he promised you a ride; and to imagine the one or two days a week you just didn't want to walk that far for something that seemed so pointless. Or the nights you spent in the emergency room with your dramatic grandmother who wanted a tube in her nose while she told you how disappointed she is in you--feigning heart attacks all night. Or the cold that turns into pneumonia (twice), strep turns into mono, broken glasses make you read with a magnifying glass for a few weeks, that jerk-of-a-boss changes your schedule and you don't get to take the final (because, really, I could deal with a C easier than I could with living in my car, again).
Then, when you finally apply for grad school, you're instructed not to "tell some sob story" in your SOP. "Don't be so maudlin." Well, I'm not trying to. I'm trying to communicate to my future graduate school that the difference between working at McDonald's forever and getting a PhD is going to be in the funding available. I want them to know that I come from a long history of generational poverty--the kind that reaches up and grabs the nearest ankle almost out of sheer spite. And that I've clawed my way out of that pit through dedication (though not as much as I would have liked) and stubbornness. I fought to get where I am now. If my dedication doesn't make up for something as meaningless as a GPA, then that school is not right for me. (And, for the record, my graduate GPA is a 3.9--I've made one B.)
Living in a drastically undereducated part of the country (Kentucky), I can tell you that some folks are given opportunities and the ones who aren't almost never get them. This is a part of the country that relies on creating a boundary between insiders and outsiders--and getting an education makes you an outsider. You grow a love and a hatred for your home and your family--you love your family but you hate their ignorance and their unfounded distrust in you. You. The same you you've always been--the little sister who got her pigtails pulled or the daughter that always spilled her food onto the table. You feel the constant need to remind your family and friends that you're still that person.
And thanks for letting me let off some of that steam.