Help! How should I purchase Nightfall?

Hi everyone I am a little confused. I definitely want to get Nightfall when it is available, but am not sure which 'pack' would be the best way for me to go.

I live in the United Kingdom and have no idea what bonuses are available through pre-order. I was astonished to discover that my friend got a kunnavang mini pet by getting the special/collector's edition of Factions, so would buying the collector's edition be more rewarding than a pre-order or can you pre-order the collector's edition and get a double bonus?

As you can tell I just have no idea so any advice would be greatly appreciated.

the mini kunnavang was to make up for a shipping delay so dont count on it for Nightfall.

i would wait until sept 15th for the prerelease packages actually come out or earlier if Anet officially puts on their site what is offered in each pack so you can make the best judgement.

on the CE hopefully your game seller will offer the option to upgrade to the CE if there is something you really want.

The collectors if you really like seeing concept art and such, it does have the special dance too, but if you don't really care, then just get the normal.