If you want an all-in-one solution for converting to dvd's with editing and authoring capabilities, look at Ulead VideoStudio 10.
Some people prefer separate mpeg encoders and authoring tools, like TMPGenc Plus 2.5 and TMPGenc Author, to name a couple of examples. DVDLab Pro is another good authoring tool, though not cheap at $250 or so nowadays (plus what you'd pay for an encoder).
None of those are the "best" software for this purpose, but they are good workable solutions for a home user. Professional software gets a bit pricey. If you want to look at them, google Avid, Sony Vegas, Sonic Scenarist, Cinema Craft Encoder, Canopus, Adobe Encore DVD---the list can go on a ways.
To copy dvds, I'd recommend either RipIt4Me or AnyDVD. RitpIt4Me is a free program that can decrypt, rip and reduce the size of your dvds to fit onto a regular dvdr. It is updated fairly frequently and can handle most any of the newer protection schemes that have been added to dvds in the last couple of years. Go to the forums for RipIt4Me to learn a bit about its use.
AnyDVD is a commercial program that runs in the background and decrypts the dvd on the fly. You can use the built in ripper, or another one like DVDShrink to get it onto the hard drive. It is updated constantly, and even has the ability to decrypt HD-DVD and Blueray if you want to pay for the premium version of the program.