I'd say stay with a 7 inch wheel for several reasons with stock back spacing. First off, if you go with a 30x9.50 or a 31x10.50 tire you'll get better protection for your wheels as the tire will extend beyond the wheel on a 7" wheel. Also, with 7" wheel you'll get a slightly "high profile" height wise from your tire because it will not spread out as much as on an 8" wheel. Now let's build upon those theories above with your wheel spacing for 8" wheels at 3.6 inches. At 3.6" of backspacing, what that means is that your wheels will stick out further and you could wind up rubbing the fender flair or inside the wheel well. Picture if you will those dorky looking Honda Civics with almost no backspacing.. ok you get my point. With less backspacing, this also means you won't be able to stuff the tire up into wheel well while off roading, hence the rubbing I mentioned. Also, by going with a lessor backspacing of 3.6 inches, you could reduce the life of your wheel bearings because the loads are extended out beyond stock and for what they were designed for. Now, if you go beyond a 31" tire, you will more than likely need to get a suspension lift or a body lift to get desired clearances, so something more to condsider there, but it all depends what you are after. Bottom line... get the wheels style you want, but with as stock as possible backspacing... Hope this helps... good luck on your wheel hunt...
Ivan
