Modest Mouse. In their defence, I read in an interview with Isaac Brock that they did a lot less drugs while making "Good News" than their other albums. Hence its more mainstream sound.
Modest Mouse isn't experimental. Also, Isaac Brock is a twat. I was reading (oh shit, shame shame shame) some interview with him in Spin (I was bored and it was on my friend's floor) and he was dissing on VIvisectVI by Skinny Puppy. Like,
hardcore dissing. Yeah, okay, we get it, you don't like Industrial. Alright. Cool. You're still a talentless asshole who plays stereotypical shit music.
I really don't get the whole Modest Mouse worship thing.
As for modern good mainstream, At the Drive In was mainstream on their last album, and that was a damned classy album. Hot Hot Heat is mainstream. Arcade Fire, mainstream. Etc. There's plenty of good mainstream, but there's also plenty of talentless twats out there, too, such as Coldplay, Weezer, U2, every nu-metal band out there, etc. There are also plenty of generally inoffensive bands that just aren't
great but also aren't so miserable they make Baby Kali want to cry. They're not good in any stretch of the word, but are consistently listenable, which I suppose is admirable if you like that sort of thing (I prefer my music to be inspired, but that's just me).