Progressive 12.5" (I believe stock is 13") 444's HD (Heavy Duty Springs, not to be confused with the overpriced, oil leaking, V-Twinkie brand).

I'm 5'10" tall, 185lbs
One up: firm aggressive feel, yet not spine tingling,
One up with gear: still firm, stable
Two up: medium soft, NEVER have bottomed-out, still stable
Love 'em.