You have tall tires too. I ran 25.5" tall tires with my 4.11s. 27" tires with 3.80s are probably like 3.55s with 25" tires... Sheer guess there...
Yeah, these are pretty tall, and you can feel the difference by just putting on a 1" shorter tire. My M/T 26X10.5 are pretty responsive with the 3.80s. They are a little bit shorter, and MUCH lighter. They are on aluminum rims, and tire and rim together weigh about 1/5 of what the BFG T/A 255/60s on Cragars weigh. Never used them on the highway, and don't plan to, but they are fun around town...
I am personally switching from a 4.62 (!) to a 3.55 right now. Knowing what the car was like with the original 3.00 and what it became with the 4.62, a 3.80 is right in the middle of all that and would be pretty good. I will echo what was said earlier ... if an overdrive is in the cars future ... 3.80, if not 3.55 will wake it up and still be fun to drive in most all conditions.