I just wanna jump in here and help further explain for
djanxo unchained the complicated relationship that the U.S. has with the Spanish language, given that I've lived in areas with a large Mexican demographic for most of my life.
First off, Chou is absolutely correct when he says that the global demand for English provides incentive for Americans to NOT learn another language. The simple fact of the matter is that the English language is used so ubiquitously across the globe that there is very little reason for the average American to learn another language other than for fun.
That being said, however, the southern United States - specifically, the states bordering Mexico (plus Florida, which is close enough to Cuba that it absorbs this effect as well) - are already heavily Spanish-speaking in the first place. The sheer number of Mexican immigrants, documented or otherwise, that have settled in that part of the country have led to sort of a cultural osmosis that leads many people in that part of the country to know at least a little Spanish; certainly it's not a large enough effect to create proficiency, but it's enough that Spanish language words often become part of everyday life in certain pockets (such as southern Texas).
As for one of your original questions: America's view of Mexico is complicated, to say the least. Yes, Mexico possesses a rich culture and a proud history, and it's important in the history of the US as well (my state of Texas wouldn't exist if it weren't for Mexico, in fact). However, the fact of the matter is that a lot of people in the United States carry strong prejudices against Mexico, mainly due to the number of undocumented workers present in the southern parts of the country ("DEY TERK ER JERBS" and all that). A good portion of these migrant workers wind up in menial labor jobs, which leads to a lot of rather unpleasant stereotyping. Combine this with the fact that the northern half of Mexico is currently under the control of numerous drug cartels and is engaged in brutal drug wars that create these migrant workers in the first place, and you can understand why many Americans would prefer not to dwell on Mexico for too long.
Regarding my own languages, I know a little bit of Spanish due to studying it in high school as well as the aforementioned cultural osmosis, but its nowhere near enough to be proficient. I'm planning on studying an East Asian language in college; Korean and Japanese are the two I'm most strongly considering at the moment.