I have seen legitimate uses for Torrents, yes. I would agree that they are mostly used to share very large illegal files, but I've seen them used to share large *legal* files as well.

I have a couple of specific legal examples I've seen Torrents used for.

1. I've seen torrents used for distributing legal ISO images of open-source software and operating systems such as Linux distributions.

2. I've personally retrieved a torrent of a VMWare machine image of a linux distro that ran multiple different browsers, for the purpose of testing your web site on a bunch of old browsers for compatibility.

3. Vixy puts some MP3 recordings of her songs up on her web site for anyone to download. When one of her songs got suddenly popular due to being posted on a widely-read Browncoat message board, her home-hosted web server (well, its DSL connection) got brought to its knees. In order to allow the song files to continue to be downloaded, they converted them to torrents to spread the load among everybody who was doing the downloading (really the main purpose of a torrent in the first place).

I admit that my desired use for torrents would be to grab TV show episodes that I shouldn't be able to grab (new episodes of Doctor Who and Top Gear that I can't get any other way because I don't live in the UK). But that's still a bit different than warez and DVD rips.