I'm running 36" TSL radials and I can get going up to about 60 on the highway. Anything faster and I can't stay in my lane due to no swaybars. All terrains are good on the roads and highways, but suck in wet conditions(off road). 35's are not that bad on the road but if you do not off road then there is no need for bigger tires.
Had 35 BFGoodrich all terrains on my 99 TJ, awesome quiet tire. Currently running BFGoodrich mud terrain 35,s on my 2005 LJ, definately has the rumble on the highway. All terrains are a great choice for highway!