realarmin, inf files are usually drivers that detected for pnp. .exe drivers you will want to install during or after sysprep. in XP you would put those commands in the cmdline.txt (during sysprep) or guirunonce.ini (during first log in):
Example of guirunonce -
for vista and windows7, it is kind of the same thing except you will put these commands in the <FirstLogonCommand><SynchronousCommand> section. I'm still brushing up on win7 so there could be more options, I'm still learning.
Hope this helps