Wait until afterwards...and see what they get you for Xmas. If it's a good enough gift, put it off until after Groundhog's Day.

you've got about another week or so... gives her enough time to return that fabulous present she bought for you and spend the money on something self indulgent for herself

In the spirit of giving, do the Seinfeld thing.
Make the other person feel like they're getting the better deal out of the break-up.
Pick your nose during the whole "it's not you, it's me" speech.

An old friend from highschool whom I am still in touch with and is a female told me she was tired of the guy she was living with and was planning on breaking it off with him after the holidays.

I cringed.

TOP REASONS TO BREAK IT OFF BEFORE THE HOLIDAYS

1. You holiday spirit will be little more then a lie.
2. Holidays are a nice time to meet someone new.
3. You aren't cheep to save a gift, besides their gift would have sucked.
4. If you haven't been happy, why act?
5. Less Stress
6. Good for reflection and nice set up for New Years Eve.
7. Have some balls man.
8. ...

MickG said:

That was my thought.

Everyone takes this time to review the future, which will be thoroughly distorted if you pretend to be together.

Plus you won't have to socialize with or schedule the other's family over the holidays.