You should also get a variety of sizes and types of tips, so you can change them round when you solder different things. I would buy a large chisel tip, a smaller chisel tip and a pointy tip. This allows you to solder in small spaces, join thick wires and have a spare tip for playing around with.
I'd say that's a bit un-necessary - Maybe 2 tips. I've managed with a 2-3mm chisel tip for about a year and I solder everything with it - you just need practice and some good solder.