Returning player, question about the Trilogy pack.

So, I played Guild Wars back in beta, and for a few months after its release.
I played until Factions was released, but I had already gotten kind of sick of the game and disliked Factions.

Now, after having no luck finding an MMO worth my time, Guild Wars is looking amazing again.

So i've considered purchasing the expansions and giving it another try.

However, if I purchase the Trilogy pack, do I get one CD-key, or one cd-key per expansion?
I'd like to add Factions and Nightfall to my original account, rather then creating a new account with all 3.
I'd prefer not to have to start over, without the use of my old characters in the new content.

Seems like a better deal if this is possible, considering if I buy them separately, it's $60 for Factions and Nightfall, where if I bought the trilogy, it's $50 for Factions, Nightfall and another Prophecy account (which my friend would be easily interested in having.)

One account key for all 3. Sorry.

FYI, you don't need to start over (although you won't have an extra Prophecies campaign) if you add the new key to your current account. The Trilogy just updates your current Prophecies to GotY without changing anything else.

One key for all three. However, you can just add that to your existing account and play Factions and Nightfall on the old characters.