alien: i cared for all of them except ash.
aliens: i cared for all of them, except burke.
alien3: i cared for all of them, except the dude that get's chopped up by the fan.
alien ressurection: i only cared about michael wincott's, brad dourif's, ron pearlman's, the cripple's and danny hayeda's characters.
predator1: cared for all of them.
predator2: all of them.
avp: i cared for weyland, skinny funny lookin guy, and the irish guy.
reasons:
alien: ash was an evil driod. but all were good acting.
aliens: burke was a company pr**k, but all were good acting.
alien3: guy in the shaft was just singing i didnt know him, all were good acting.
alien ressurection: the 5 that i mentioned gave the best performances, the rest were idiots, including ripley's clone's one liners.
predator: the film is just a masterpiece, and every actor gave an incredible performance.
predator2: all actors gave great performances, cared about them all, except the jamaicans and the columbians, cause they were just scum, lol.
avp: the one's that i mentioned were the only ones that gave decent performances.
so, bottom line: it comes down to how convincingly the actors portray thier characters. at the same time, burke, ash, jamaicans and columbians were great performances, but they were pr**ks, so i wanted them to die. the rest of the characters i didnt mention that i didnt like, were just poor performances in my book.
90% of whether i care or not comes down to acting.