DVD Decrypter is about the best tool you can use to quickly rip an entire DVD to your hard drive and will keep all the structure (subtitles, menus, alternate languages et all) completely intact. It will also remove the copy protection.
About the only time it has a problem is with DVDs that are intentionally corrupted with bad sectors to prevent copying, sometimes it can just work slowly through the bad sectors, sometimes it can't. I've had several films come through this repairing unharmed and one which simply Does Not Work. These are the exception rather than the rule, most films rip fine.
After that you can do what you like with it, either keep it as a set of DVD files which you can then simply drop the
VIDEO.VOB file into Windows Media Player to play it as a normal DVD (or you can associate the extension with WMP or $INSERT_FAVOURITE_PLAYER_HERE$).
This does mean that you may be wasting quite a bit of space though and personally I convert my DVDs to mp4 video using Handbrake, which is another excellent free tool and saves a lot of space compared to raw DVD files.
As mentioned by Nifle Handbrake is a very full-featured encoder and supports various audio tracks and subtitles and, paired together with a player like VLC or MPC-HC, you can get all the joy of your DVD without all those annoying animated menus and "You're a Pirate" accusation screens that appear even though you actually bought the DVD.