You always want the listed tread width to be equal to or slightly greater than the listed wheel width. Manufacturers have this info. on their sites, and tirerack.com has a lot of info too.
For a 8" wheel, to get the tread width to be the same you are looking at 255 and 265 width tires. But usually those are 30" tall or more so I can't say whether they'll fit or not.
'92 YJ - heavily modded
'96 ZJ - heavily modded
'05 KJ CRD Limited - 370 lb./ft. from a 4-cylinder and trail ready. Pure awesomeness.
'11 Mango Tango JKU Sport - Mods
'12 Dozer JKU Sport S - 6-speed - ACE rock rails - Max Tow package - Daystar spacers - 33x12.50 Duratracs