Well... really depends where you're hiking.. If you're back countrying and you're not on an established trail....
I would take some survival courses... first aid, ect. You'll need that. I would bring a gun if I were you... that's just me. Bear mace is a MUST, so is bringing light and durable clothing and equipment. Be prepared.... the mosquitos up there actually drive some animals insane... that should be a clue as to bring plenty of repellent.
It's a unique place... you'll need everything from sunscreen to a jacket...
I wouldn't recommend just hiking off into the back country though. People die that way. That guy from "Into the Wild" was a complete idiot... no intelligent person would venture off into there without being completely prepared and knowing all your checkpoints... ranger stations, nearest transportation routes, nearest rivers, knowledge of local wildlife, etc.
I actually spoke to a ranger up in Northern BC. He said the cases like the guy from "Into the Wild" aren't unique, they're actually quite common. Young kids from cities all over thinking they can go into the woods to "find themselves"... more times than not it ends up being a body retrieval effort... not even a rescue effort.