The thing I don't like is that it will give racist cops an excuse to harass anyone who even just looks like they're Hispanic. I don't like to say bad things about cops, but they are human and therefore not perfect.
I think illegal immigration is a problem, but not as big as everyone makes it out to be. If you really think about it, they are this country's source of cheap labor. They do the jobs that citizens won't. There are people who won't work in a fast food joint because they believe it to be beneath them, which is bullshit, but what are you gonna do?
Also, people bitch that they don't pay taxes, well, set it up that they can pay taxes without fear of being deported. Some probably won't, but some might. After all, they're not horrible monsters, but rather human beings. They're here for a reason. They risk their lives to get here, so what they're running from must be pretty bad. Hell, maybe the answer even lies in making entering the country legally easier. Think of all the extra tax money.