Well, if money isn't a problem I would tell you to toss the spacer and get some Radflos, maybe the TC UCA if you felt so inclined. You may also want to address the weak stock spring packs...
Anyway, I'm sure that's not the advice you're looking for. What size wheel will work with some nice all-terrain tires? If that isn't a typo, you're probably going to have to pick the all-terrain tire of your choice and then do some research to figure out what tire sizes that manufacturer has made available. Keep in mind there aren't too many wheels that fit our bolt pattern and clear the calipers. More and more people are now running spacers and adapters to address this problem.
Now if you're asking about how much tire you can fit in the wheel wells, that's another story. You've probably figured out that you can run 33s at stock height. Even with a 2" spacer/shackle lift and a body lift, you're probably going to have to trim metal to fit 35s.
I think the guys over at clubfrontier.org have spent more time discussing custom 2" body lifts (nobody that I'm aware of makes a 2" kit yet). Spend some time searching both forums and I'm sure that you can make a well informed decision.
Good luck.