nothing better then rounding a massive Glamis bowl in 5th pegged.  The g's forcing the suspension to flatten out.   

It's all about preference really.  When i dune i like 3rd to be my low gear.  I click 4th coming out of dune trails into to straight-aways and 5th sometimes in the open areas.  I use 3rd & 4th gears the most.  Although, i do think my gearing is a tad low even for that.  Find myself using 5th a lot.  That's why i'm switching to the 14 front.  Well, one of the reasons anyway.