I think you'll find that a TJ with 31's, 2" lift, swaybar discos and a front locker are far more capable than anything on 33's with open diffs in the rocks and wheel lifting twisty stuff. If the money saved by not going to 33's & 3" lift buy a front locker you'll be laughing offroad. When my front locker went in it completely transformed the jeep offroad, especially as i'd had 5 years of open diff jeeping prior.
I would say that my TJ is 'finished'. I tried 33's for a few trips (borrowed from a mate) and i ran 32's onroad/offroad for 12 months. I just didn't like them as the TJ felt woeful onroad, had no power (even after i've had my diffs done) and used heaps of fuel. They'd prob be ok if i went with a 9.5 or 10.5 wide tyres but i reckon the reason i didn't like them is due to the 11.5/12.5 width. They were great offroad but rubbed and i was worried i would break something. That's not to say they're not for you, plenty of guys runs larger lifts and/or tyres and love them.
I have now gone back to 31's as for me the onroad function of the jeep is just as important as the offroad. I don't do the harder stuff i used to anymore due to time/family/financial restraints. Sure there's going to be heros out there saying: "that Jeeps bloke is a wimp", but i have a mortgage, bills and a family to look after so driving around with big tyres trying to increase the size of my wang and avoiding the police doesn't interest me LOL
. I've had it for about 10 years and i've set it up the way i want for the way i use it and if anyone doesn't like it, they can bugger off. Same applies for you, if you want it just do it. If my TJ wasn't diff locked it might be wearing bigger rubber but with lockers and diff ratios done i have no desire to go bigger as the jeep goes everywhere i point it. Plus, tyres are $100ea+ cheaper, it uses less fuel and has heaps more power and the boys in blue don't even give me a second glance.
If you're after "the look" of big rubber then nothing is going to stop you, just go and get the rubber with a cheap lift. But if you're after better offroad ability there's no substitute for experience. If you're only new to your TJ i think you should drive it with just 31's for a while, get some experience. Only then will you have a true understanding of what you want and most importantly why you want it
cheers