For me, it's the Yamaha 0X99-11. I fell in love the second I saw it!
Tandem seating, F1 derived NA V12 with an 11,000rpm redline, 2,200lbs. and a 6-speed manual. It sounds amazing!
I guess the closest thing to this would be the Gordon Murray T50 at this point. Yes, McLaren F1 is too, but I'm not driving a $20 million car! Or a $2.5 million dollar car for that matter in the T50, but I can dream.