One important thing you need consider when planning your trip – public holidays in destination you are heading to. Of course it [public holidays] can be the reason why you are going there, otherwise it is better to check calendar what is going out there.
Even identically named holidays can happen not on the same day. Like New Year celebration in most countries is on 1st of January, but Chinese New Year is on February 14th, 2010 and date is different each year. In most countries Christmas Day is on 25th of December, but orthodox celebrate it on 7th of January. Thanksgiving in US is on fourth Thursday in November, but in Canada – on on the second Monday in October. This list is almost endless, as even in different states or provinces of the same country holidays can be on different days. For example Labour Day in Australia in 2010 – on March 1st in WA, but on March 8th in VIC and TAS. Probably on any day of year it is possible to find country which has holiday on that day.
Personally I prefer not to travel on such days (local holidays is exception). Not only because it is more difficult to find accommodation and it is expensive, but also grocery shops, gas stations are closed earlier or totally closed during these days, national parks are getting crowded. It easy avoid these days by looking to calendar and here is starting point with listing of public holidays in different countries.