Pretty obvious from the title. I have a friend back in my old town who loves Killzone and has convinced me to get the second. Just wondering if I should rent the first one to catch up on the story, style and controls.

I don't think Killzone will have many of the features that are going to be introduced in this game.

Killzone wasn't a great game anyway. The story wasn't in depth so there is no need to experience, unless you really want to.

Youtube the cutscenes from KZ1 to get a rough idea of what happened. I thought it was a great game however tedious it got.

I'm just going to wiki killzones story. I'd suggest the same

I would say yes if you can manage it, people can say that the story lacked depth but it was pretty riveting nonetheless, plus the voice-acting was exceptional (Not many games have actors of the standard of Brian Cox and Sean Pertwee providing voice talents).
Some of the cutscenes were very memorable as well, the one where the villainous general reveals himself and again when said villain repeatedly bashes guy's head off desk spring to mind.