Not trying to be cynical here but I have not found anything that I could say that for. Guitars are just fastened together pieces of wood and Wire. I have have yet to find one that I would call the best I will ever play. As my playing changes so do my needs for equipment. When I am old I will probably want one with a pill dispenser and Ben Gay pump.
Maybe my old JCM 800 Dual Reverb but I say that now cause I don't have it anymore.
An Amp that carries itself would be very cool too!
Wow...I think I would have to go with my Riszanyi Custom Shop Tele and Diezel Herbert. As noted, the Tele can do just about anything and the Diezel speaks for itself.