I wish people would stop limiting the concept of "interracial" to only black and white. Technically, interracial could even be a hispanic getting fucked by an Asian. Usually, when people are talking about interracial, they're talking about watching a black man fucking a white woman.
Anyway, I only enjoy it when they are not calling attention to the fact that one of them is of a different race. A fuck is a fuck is a fuck, but I get so turned off when they start saying shit like "like that black cock" or "that white ass" or "this latin pussy" or things of that nature.
Also, I'm more likely to enjoy it if it's a black/hispanic/asian woman being fucked by a white guy. That's because I like to imagine I'm there fucking the chick (isn't porn supposed to put us in a fantasy world anyway?). As a white guy, I can't do that if the dude in the movie has a black or brown dick.
Additionally, as someone previously mentioned, I really hate it when it's some 'gangsta' looking/acting guy (which is true no matter what race he is). I can't stand thugs. Sadly, most black guys in porn act exactly like that.