I like Jet a lot. They sound like they could have been the opening band for Bad Company back in the mid-70s... and I dig that about them.
The Darkness... well... I think that "I Believe In A Thing Called Love" is catchy and I dig it a little bit. But... I tried to listen to some of their other stuff and it is horrible. Just horrible. And I agree with RHogan that the vocals are what absolutely make it unlistenable. While it works on "I Believe..." I'd rather dive into a swimming pool filled with double edged razor blades than listen to an entire CD worth of it...