Hi Mostly Slowly, I suspect you posted a reply to the wrong thread, but happy to answer anyway.
Best Bike - I tend to use big trailies for most of my commuting. My best ride is a BMW R1200GS, but that's not very reliable, so I get more use out of my R1100GS, Yamaha Super Tenere (the old 750), KTM 640, KTM 950 Adventure etc. When the weather is better I often use a smaller bike, such as my BMW F650CS.
Best tyres - Whatever I can find part worn either through the owners websites or at my local independant bike shop. It is more trouble changing tyres every couple of weeks, but the saving over a year is more than worth it. Metzeller Tourance tend to be my tyre of choice for the big trailies.
Best Gear - Again, much depends on what comes up second hand on owners and enthusiasts web forums. I sometimes buy new, but would rather pay half price for something which has been bought by a less intense rider, and has gone out of fashion with a thousand miles or two use, which I can then wear out over 20 or 30 thousand miles.
Hope this helps, sorry I don't really have any pearls of wisdom to impart.