Yes it is worth it, but I'm still in the midst of celebrating Christmas and haven't finished swapping presents yet. So not one day for us.
Personally, I prefer to start early, finish my shopping in Nov and use Dec to enjoy doing Christmassy things as a family.
I also never buy tat either. Don't buy smelly sets (I don't know anyone who actually appreciates receiving these) but my DDs do get a lot of practical items each year that I can buy as I go along. Vests, pants, socks etc can all be bought whenever in the next size up, likewise pens, books and stationery bits are also easy to buy. I get the practical presents bought early, which means then I've only got to buy the DDs toys / requested items in Nov. Other family gets spread out in Oct / Nov. This generally works well for me.
However, this year I started working full time again, had OFSTED and a hard term meant I was shopping up to Christmas Eve. Whilst Christmas itself was lovely, the run up was no where near as nice; we didn't find time to do all the Christmassy things I love like going ice skating at the shopping mall, visiting Father Christmas or the Panto trip. I have to say that this Christmas period has been no where as good as a result.
Next year, I'm back to starting my shopping in the summer.