Most DVD movies come on DVD9 blanks. If you record to a regular DVD5 (which holds about 4.5GBs) you will need a program to shrink the file.
This is what DVD2OneX excels at doing -- you can even batch jobs. Then I burn my DVD using Toast. (DVD2OneX can burn a DVD, but I prefer Toast.)
Also, some folks just use Toast which includes an app called Popcorn, to do what DVD2OneX does. So you can shrink and burn with Toast.
To squeeze/convert a movie to a format/size that your iPod can play, I would suggest using Handbrake.
So you would use MTR to put the DVD on your HD. Then Handbrake to convert the file to one you could load onto your iPod.
What I like about making backup copies is that when I travel, I never have to worry about my DVDs getting scratched or lost. If so, I still have the original at home.
One of these days, after Apple introduces a true video iPod, I may just convert everything to the iPod format. Currently I have a few movies/shows via iTunes which I find very convenient.