For what its worth my current jeeps have the following setups
1. 2007 Rubicon with stock drive train aside from 4.88 gears and 35s: 4.46 (first gear), 4:1 (low), 4.88(gear) = 87.06 even with the v6 i find myself wishing i had a lower low gear when I did the Rubicon last year. Though I still say the 2.5 4banger has more will to live at low rpm than the 3.8l
2. cj2a proto jeep: 4.3l v6, SM465 (6.55 1st, 3.58 2nd), dana 18 with terraflex 3.15:1 low range kit, 5.13 gears, and 35s. results 105.8 in 1st, 57.85 2nd. I find myself using 2nd gear for most trails in this rig but the low 1st gear is great for playing in the rocks as you can practically momentarily come to a stop without stalling (backlash starts adding up). Obviously with the 4 cylinder it would be nice to be a bit lower if you are crawling in the big rocks / ledges