It all depends on what you wheel and the look you want. If you want it to look wide and beefy a 15x10. If you wheel in the rocks more times than not, Get 15x8 with 3.75 or less BS. IMO i would run the 15x10's no matter what, Looks better with a wider stance and on road driving is a little better. The only down fall is if you want to air down to less than 10psi consistently. I say consistent as i have been at 8psi and never popped a bead, But not to say i wasn't lucky.
YJ, TJ, XJ, ZJ..... I like jeep's too much!