I guess it depends on your definition of 'heavy'. You can take two Queens songs and one will be heavier than the other...but then you can compare both those bands to heavier styles and they'll be lightweight in comparison. Homme has stated before that he's about repetitive riffs that drive the song, in an almost robotic way. Foos were heavier to begin with (but then Grohl played everything on their first album, so thats probably a reason). It's also down to each band members style - as people have mentioned, Nate Mendell came from Sunny Day Real Estate, which a) are awesome (Diary is a superb album) and b) but really that heavy.
Even though they don't come across as really heavy, The Foos are able to really kick it up a bit when playing live. My own experience is at Wembley in 200...8 I think it was. A night of heavy music and pouring rain (not to mention Led Zep) was a life-defining evening.
Is that where the third gig is. More chance at Brixton as its quite a bit bigger venue.
Get in !!!!
2 tickets for Islington
Shame on you mate - behaving like that. Tone it down next time, eh?