Guess it depends on how you define useful. Versatile or most used because of the style of music you usually play. Most versatile in a Tele Duncan Vintage Mini Humbucker in the neck and a BG1300 in the bridge of a 52 Hotrod (I replaced the original bridge pickup). 5-way switching with normal 3 Tele sounds, bridge with no tone control and bridge with cocked Wah tone. Most used Tele in my church gig (So, I guess most useful for that) Custom shop Tele Thinline with Tele Texas Specials. Most used guitars for my church gig Custom Shop Strat with HSS (too lazy to pull out the traveler right now) PRS Custom 24 with splittable humbuckers.