In no particular order (save #1
):
- Ogilvy
- Caples
- Reeves
- Kennedy (John not Dan)
- Hopkins
- Halbert
- Lasker
So many more are worth noting, that it's almost impossible to stick with just seven (
Bencivenga, Schwartz, Carlton, Makepeace... 
). The thing is, every writer who actually creates his or her own work brings something different to the table; so if you're constantly reading new copy, it's possible to be influenced by even the newest writer's style. Just my opinion, of course