For me, limiting my response to stock production vehicles:
Depending upon the needs of the day:
1991 V3500 Crew Cab, SRW, 454, 4L80E (Saw one listed recently on eBay for $115k)
or
1991 V2500 Suburban, 350, 4L80E, barn doors.
Of course love the Blazers/Jimmys too. Pick your favorite year...