well being that im a glass man my favorite tool is the fien knife, its a vibrating tool that cuts through and type of glue or silicone with ease, makes glass replacement a snap...
Well, putting in perspective of "for the bike"..............my bike jack is probably used the most for everything from cleaning to repairs.......after that....well....I guess it depends on what day you ask and what I have recently worked on.....but I would have to say my Snap-on swivel head 3/8 rachet or Snapon long handle needle nose pliers come in pretty handy also.... unless I am taking wheels off of cars then it would be my 1/2'' impact....of course if you are taking the fairing off then it would be the torx bit sockets... or changing oil it would be the strap oil wrench with the opening for the 3/8 rachet....which of course I use the previously mentioned swivel head.....and if I am welding something a good pair of vise grip C clamps is always a necessity.....................OK OK I admit it....I love ALL my tools and refuse to pick ONE favorite... there I said it.....;-)
Unfortunately, the tool that gets used for the more complicated jobs is one of those little thin plastic cards.Those guys at the shop are really proficient with them...