Like I mentioned, there have been too many covers of this song to count, so let's start with the Cure's version. This version is pretty good, keeping the same spirit as the original. The basslines are a bit fuzzy and loud which distracts from the vocal a bit. Overall, a pretty ok cover. Joy Division did open for The Cure for a bit during the late 70s as well. Here is the version from the Cure.
Now, this version from The Swans happens to be my favorite and I have said before that this should be the only cover that should exist because it's sooo good. Actually there are two covers of this song from this band. Let's look at the version with Jarboe on lead vocals first. This version is my favorite of the two because of her beautiful, ethereal vocals and the nice guitar on this. It gives a whole new meaning, look and sound to the song. It's nice to hear a female voice interpret this song. So pure and beautiful.
The following is another cover by Swans. This time it featured Michael Gira on lead vocals, though Jarboe does backing vocals. This is more similar to the original, though (and many Joy Division purists will dislike the following comment), I feel Michael Gira has a better voice than Ian. Ian was more of an emotional singer but Michael is the better vocalist here. I love the use of guitar and the vocals of Michael and Jarboe here. This to me is the definitive version of this song, a must hear.
The list is endless of bands who have covered this. It has been covered by U2, Fall Out Boy, Heavens, New Order (which is Joy Division minus Ian), Bjork, Dave Gahan, Thom Yorke (of Radiohead), Jose Gonzalez, Apoptygma Berzerk, Moonspell, Arcade Fire, John Frusciante, among tons others. I think only Love Song by The Cure has been covered by more artists. Nevertheless, check out the covers I posted. Thanks again!