I'd get the Bethesda pack but I hate how their games are put together. All the characters have the same voices, some people are essential, etc, etc, etc.
New Vegas seemed to do it right, anyone with a name has a unique voice and no one is essential.
In Oblivion it seemed like the entire voice acting budget was spent on Patrick Stewart.
Fallout 3 also suffers lack of voice acting.
Skyrim as well.
New Vegas (A game not made by Bethesda) added a wide variety of voice acting.