15's on my Blazer, 16.5's on the tow rig.
I would trade the 15's on my Blazer (trail rig) for anything else, they take a lot of grinding to fit a D60 front, I've had 15x8's w/2.75" backspacing and 15x10's w/3.5" backspacing. They always rub, you'll get to a point that they won't rub in the garage and then go wheel them for a while and the combination of pad wear, rocks/sand/mud etc all tear up the caliper and wheel. You'll eventually destroy the wheel and possibly caliper, either of which could be a really bad failure. Salt on the roads makes that exposed steel that much worse.
15's really don't work well on an 8 lug front end. I, like most, got into it because I ran into a great deal on some brand new 37" MT/R's years back for a 15" wheel so I simply grabbed some 8 lug 15" wheels to match. Later, I found a good deal on a set of used 42" IROKs for a 15" wheel and switched. Then I replaced those wheels with beadlocks. Now I'm stuck with tires and wheels that are ok but could be better and it's big $$$ to change everything now. If I had gone to 16" or 17" wheels earlier I wouldn't want anything to change now.
I run 37x12.50R16.5's on the tow rig primarily to keep RPM's down for the diesel, plus the tires are super cheap! That wheel size is bad for four wheeling unless you run double beadlocks and even then the H1's typically need to be recentered and need a rock ring which throws their "cheap" price right out the window.
To sum up my opinion for a wheeling rig, 16's and 17's are good, avoid 15's and 16.5's!
Only downside is having to grind the calipers.
