The BBC Radio 1 playlist is a good guide to transient mainstreamness; the tracks you list seem to be a mixture, with Dizzee Rascal and the Chemical Brothers squarely mainstream, the rest more off-kilter (to the extent that I haven't heard of half of them).

For all I know, it's just the personal favorites of the guy that hosts the show.

IMO all the best music shows are like that.

Peter