I have the stock sized Zeons, 275/60/20. I think it looks good but I think a slightly taller tire would look better. Both the Coopers and the Nittos are available in 275/65/20 and the Nittos are available in 295/60/20. I'll probably go with the 295/60 Nittos if I still have the truck whenever these Coopers need replacing although they are a fair bit more expensive than the stock size.
06-08 chrome clads w/33" Cooper Discoverer H/T Plus, Mopar tailgate spoiler, debadged door trim & tailgate emblems, 13" antenna, LED dome & maps, Magnaflow 22" SI/DO, 18% tint, "HEMI" hood spears, VHT tinted tails & third brake light, Lamin-x optic blue fogs, leveled w/McGaughys 2" drop shackles.