It's a fun debate because you know for certain that someone on the coli will disagree with you. Isn't that half the reason we're all here? If people knew that everyone on here would agree with them completely anyway, they would probably not bother trying to sell their idea.
Anyway, there are probably tiers of hotness, and discussing who is hotter than who could probably vary within those tiers. I mean, you have bottom tier like Roseanne Barr or that gross lady from "The Office."
Then you have a step up which is the kinda 'Plain Jane' type with a really average body, perhaps with a slight paunch and some less than desirable facial features. At this point, you're thinking about the decent-looking chick from the job that you might smash on if you were on a cold streak and/or bored. Nothing to be outright proud of but nothing to be too ashamed of either.
Then you have another step up with girls that are pretty fit and have good looking faces. The kind of people that anyone would have sex with and definitely not be ashamed the next morning. At this point you're thinking of the cute fitness instructor, the aspiring model who probably won't make it despite being pretty cute, or maybe a really hot yuppie chick who has an extremely high (and well-deserved) opinion of herself because she's hot and successful.
Then there's the top-tier types that makes you do a really pronounced double-take and go all bug-eyed out of excitement. We're talking movie star status at this point. The level of Scarlett Johanssen, your Alessandra Ambrioso, Beyonce before she started dying her hair blonde and wearing blue contacts, and Eva Longoria. These are extremely rare but also very exciting to meet and THRILLING to smash.
This is just a loose outline. If you think that there needs to be more or less tiers to this, go ahead and say so, but you get my general idea, hopefully.