I like toys for oral and anal. I can't get anything wider than 2.25" into my throat so my oral toys are all between 1.5" and 2.25"
For anal, 2.5" is the biggest I've tried and I didn't enjoy it. Again, I think 1.5" to 2" is my comfort zone.
I've only got two toys bigger than 2" and they don't get as much use as my more "normal" toys.