Technically, the only Christian holidays are Valentines Day, St Patrick's Day, Easter, Mothers Day, Fathers Day, and Christmas. Many include Halloween, but some Christians feel that Halloween is a Devil worship holiday instead. The patriotic holidays (in the US) include Martin Luther King Day, Presidents Day, Memorial Day, Flag Day, Independence Day, Labor Day, Columbus Day, and Veterans Day.
Which leaves a few out. There is no grounds for New Years Day to be frowned on, as this simply marks the start of the new calendar and a chance to purge old bad habits and start new good habits. The witlesses do use the prevalence of drunken bouts to dissuade others from observing it, but you do not have to go out and get drunk (or drink and drive). April Fools Day is not, as far as I know, religious. And Thanksgiving is simply a day to reflect on the bounty of the harvest, and can be used to give thanks for the harvest in any format you see fit. However, the witlesses do not apply this technicality--they ban first and ask questions later.
One question they should ask is what Colossians 2:16 has to say about judging people for observing different festivals. According to this scripture, if someone celebrates Christmas even if off date, so what? If they observe festivals, so what? Or, if they choose not to participate in certain festivals or participate in a limited way, so what? This is one more thing that the witlesses fail to uphold in their own Bible, when in fact they claim to uphold the whole thing and to be the only ones to do so.