What is the best way to make an ISO file out of a DVD?

"ImgBurn is a nice, free tool for creating disc images as well as burning them.

Be forwarned that the installer off the imgburn website contains the opencandy adware - so you may want to look for the alternate, adware-free mirrors"

"Like @Joakim points out in the comments: you can also download the iso again. But if you want to save on bandwidth:

LC ISO Creator is very small, lightweight, free and portable!"

"You can install Windows 7 on up to 3 computers with the same key (Win 7 FAQ) and the key is not tied to a particular ISO download.
An easy way to create an ISO from a disk is to use ImgBurn."

I like MagicISO ... not free, but well worth it.

"MagicIso

it offers Virtual image creation, burning existing images, support different types ISO, UIF, NRG, BIN and CUE, mount Virtual CD/DVD drives and more.

[EDIT]

I didn't know it's not free, though it doesn't require any registration or anything like that!"