I know you don't want a much larger tire, and you don't offroad much...but, the 275/70 is a great tire size for what you described.
It is a bit wider, which gives a bit more traction, a little bigger around, than the 255, about an inch each way...but times four, its like having the traction increase of an extra tire's contact patch.
I ran 275/70/16's as the first replacemt for the Grabbers on my '01X, wow, what an improvement!
Since you chose an All Terrain type tire, I assume you go off road at least once in a while, maybe just dirt roads/firetrails, but something during vacations, etc.
If you never go off road, a Michelin Cross Terrain in that size is an amazing improvement as well, and on road, even better than the REVO...the REVO is amazing in snow, and so is the Michelin...if you go off road occaisionally, or want the option, the REVO is better though.
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- TJ
2001 Xterra '03 VG33, SE 5 spd, 305/70/16's, Revolvers, UBSkidderz, Doubled AAL's, 3"SL/2"BL, winch/bumpers, skids, sliders, OBA, Snorkel, pine stripes....
Friends don't let friends drive stock.
http://www.gifsoup.com/view/501230/tj-tackling-crawlers-ridge-o.gif