You still use E:, F is just a user partition you can add games, films etc to.
Mine also has a G:
You should know that the Xbox only supports up to 127gb hard drives natively, you need an extra utility to see the rest of the drive.
I have a modchip in mine, the bios on this see's bigger drives automatically.
Edit i misread your post., yes move all the large stuff to F:, E: is used for dashboard like XBMC if i recall.