Although I don't have any personal experience with a 270, a buddy of mine does and he shoots the 150VLDs as they have the best BC of the .277 bullets.
I do have experience with 7mm bullets. The answer here is that it depends...
If you are shooting a 7-08, the 120grain bullets are the go-to bullets as the 7-08 is limited to shots around 500 yards. As a result, it is more about velocity than BC. 120grain bullets are great for shooting everything from varmints up to deer size game.
Personally, I have a 280Rem (My 280 - Updated!
) in it, I shoot the 168VLD at 2780. It has sufficient horsepower to take deer at 1000yards.
If you go with one of the bigger 7mm's (7remmag, 7rum, 7stw, 7wsm, 7saum etc) you should seriously consider the 180grain Berger Hybrid.