I always make my bosses tea/coffee.  It has never occurred to me that they would make their own!  They have their drinks at set times of the day and I pretty much view it as part of my routine.

When I worked in the computer department, my boss and I took it in turns, but it was kind of a different sort of relationship to the one I have with my current boss.
I sort of like taking care of him!  I don't mean that to sound weird, but I know that it must be really stressful for him running the company so I guess bringing him the odd drink to keep him going can't hurt!

I always make the refreshments for visitors as well.  I took someone's advice from this forum about making a note in your Outlook Contacts file about how people like their tea/coffee and it really seems to impress them when you 'remember'!

Best wishes to all,
Nicola.