It'll work out as £20.-- per person this way. Rather than £27 (pre-order price).
I'd also like to point out that the Steam pre-order price is the same as Amazon/Play.com, which is a first as Steam is usually over priced.
So going for the 4 pack would work out as very cheap indeed.
I'm interested in going halves (quarts?), although I can never find the time to play L4D1 anyway. So might need to think about it. Anybody know when the pre-purchase finishes/ (ie, deadline to decide if I want to get it).
@Zofo, if you order off Steam, it'll be Steam automatic steam download when it's released (and demo download before that). Very hassle free - as with all valve games.