This has been a favourite question on several forums:
What's in your Stitching bag?
I love my stitching bag! I rarely go anywhere without it and I keep it stocked with Must Have items:
2 highlighter pens
Notebook for writing down ideas, chart alterations
extra packs of size 24 & 26 needles
retractable tape measure
Tide Stain Stick
two or three small charts w/ all necessary material for stitching
one bigger kitted project
extra skeins of DMC Black, White, & Ecru
Eileen Bennett's Red Book of Sampler Stitches
Udderly Smooth Skin Cream (Tube)
There may actually be a couple more items, but I'm afraid to look at the moment!