The hardest thing for me to pack is always toiletries. This always takes forever. There is so much that is needed every day! I decided to permanently keep one set of everything in a travel toiletry suitcase. This works best for cheaper items though, I can't justify letting my nicer creams or cosmetic items expire sitting in a bag.
Just reading back over what I've missed.... I just ordered today, what I believe may turn out to be the ultimate cosmetic bag. It is by EMME. Which I had never heard of. It is a hanging cosmetic case with a zip off clear quart-sized pouch for TSA liquids attached. So I can leave the little bag out for TSA and then zip it back into my toiletry case at the hotel. So everything stays together. It also has another small pouch that zips off that I am thinking could be for makeup that I carry in my purse, and then again, can zip back into the bag at the hotel. I always used to end up with multiple bags of this and that, it seems, and then had to try to remember where I stashed everything. I have high hopes for this bag.