Thanks everyone for your suggestions and feedback:
I guess I wonder about the nature of ukemi- if ukemi means to recieve then why on earth would you ever resist?
Sometimes nage does not have my center, but that doesn't mean i resist him- I dunno
To me as uke, I don't really "resist" (or, as it is called at our dojo, "punk") tori, however, I do often walk out of a technique if it lacks in balance taking. So, I guess uke should be...neutral. He should be intent on attacking, not making tori's job hard, but he should not be like a house of cards and fall at the lightest touch either. That is just my thought.
*Take is with a grain of salt as I have only been formally training for 2 years*