I'm part way through the 'big clean' as well. Combined with a spot of home decorating, it is not entirely working, but this weekend will be the end of the painting and the start of the cleaning and Christmas decorations.
I always deep clean the lounge before the tree goes in, and clean all the windows as well. Carpets got washed in the summer (DIY job) but need a good vacuum including well into the corners, under furniture, and skirtings wiped.
I've decluttered my room, and the garage, and scratched the surface of the DCs bedrooms, mainly clothes. I sorted out some toys /games that are too 'young' for them to play with any more and if nobody asks where they are by next week then they're off to the local Barnardos.
I'm blitzing the spare room /study / extra toy and book storage space next, and then plan to just keep up the tidying and lighter cleaning. The kitchen needs a good clean as well, but I'll do that in a couple of weeks so that it just needs quick maintainance before Christmas.
Cleaning our house is not that hard, but putting away / sorting / disposing of the random crap that accumulates every day seems to take forever. I am convinced by the mantra that mess attracts mess - once someone (looking at you DH) starts a pile on the breakfast bar, everyone else spreads their clutter out and then there's nowhere to actually put food / sit.
Some great tips here. Does reading about cleaning count as cleaning? 
I started a thread back at the start of the month about sorting out home / life / health before Christmas. LInky here: www.mumsnet.com/Talk/Christmas/3408121-Anyone-up-for-a-sort-out-myself-my-house-my-life-for-Christmas-thread