Funny you ask, I actually spend alot of time thinkging about this!
I have 4 categories (for bigger deer) "nice" "big" "giant" "Monster"
These are just personal ratings, I know everyone else has different ideas.
A nice buck for me is a 140-155 mulie, doesn't matter if its typ or non, still measuring that much bone.
A "big" buck is one that goes 160-175 or so. These aren't net scores, just gross. Symmetry and cheaters dont matter so much to me, just measure the bone!
A "giant" buck is a 180-195 or so. Now I will start to separate the nontyps a bit. I think for a nontyp to be a giant, he's got to be 200-210 at least.
The "monster" is just that. 200+ typical or a 225+ nontyp. I think even the lowest end B&C nontyp is a monster, but I dont think the lowest end typ is a monster, he's got to be over 200 to be a monster.
This year, I'll pull the trigger on a "nice" buck, but would love to hit that "big" buck category. I think a 160+ mulie is a big buck!
Good Luck All!