Avons for me too. Tried the Bridgestone 020's and the 021's and just didn't like them in the wet greasy crap much. Great when it's WET, with a capital pissingdown, and supurb in the dry, but that drizzle, greasy, diesel crappy slipperyness they were somewhat arse. Never felt planted and had a few minor moments of slideyness even going fairly slowly, especially on roundabouts. Shoved the Avons on (which I had on my previous ST) and they are something else. Always planted, always sticky and nicely profiled. Good wear and just nice for tootling or tromping on.
Even 2-up, all over Ireland and France, with loads of luggage, and me being a right fat knacker, they have worn really well and not squared off noticeably even with hundreds of motorway miles.
I like 'em!
I also had Conti-Road Attacks on my previous ST, and they felt really great too. Tempted to fit them next just to see how they fare against the Avons. Coz they are cheaper. And did feel as good on the ST. But I heartily recommend Avons.
Never had much joy with Michelins though. Any make! Z4's were the absolute worst tyre I ever had fitted on any bike.