All the essentials of course! That's how I got the nickname "mamma dee", high school I carried around a tote that had everything but the kitchen sink. Needed something? "Go ask Mamma Dee." I don't carry scissors, a hair brush, and a set of permanent markers anymore, but there is a list of items I cannot leave without. Split in two, the top half is the never leave the house without, even in a rush, and the bottom is my normal selection of must-haves.

Travel Credit Card - Bank of America has a great credit card that is specifically designed so you are not charged any extra fees each time you use it in a foreign country. No extra fees, only the exchange rate for that day.
ID - Duh
Passport - Keep on your body at all times! I cant tell you the number of horror stories I have heard about someone getting everything they had stolen while traveling. Without your passport and a credit card, you will have a slim chance of making it home easy. I carry my ID, Passport, Credit Cards, and some cash on me in a sling I wear under my clothes. It can get annoying sometimes, but then I think about loosing everything, and a little discomfort is ok with me.
Cash
Cell Phone

PowerCore+ (the blue cylinder shown above) - This charger has saved my life quite a few times! Charge it up beforehand (otherwise its useless) and can charge your phone almost fully with it. If you don't want to spend a butt-load on the Mophie case, this is a great alternative, AND its only $10! (Check it HERE!)
Pen
Keys
Document sling - Harry Potter themed of course!

The full sha-bang (in addition to those listed above):

Canon 6D (AKA my baby) goes everywhere with me, even if its the weight of a small child. The quality and beauty of the Canon 6D beauty is amazing and also a fraction of the price of other full frame pro cameras. I got the Amazon Deal and packaged everything together for some extra savings (Check 'um out!)
Extra battery
Wall Charger - For when you find a place to take a breather and plug in.
Extra SD card - Because I take WAY too many photos and even have a spare in my wallet (its come in handy before!)
Business Cards - Never know when you will need to strike up some business!
Shopping Bag - Most grocery stores make you buy your own bag, so I keep onw with me always and it lines the bottom of my purse, taking up no extra room and giving a little more cushion for my electronics.
Light Sweater - Same goes for a sweater. The weather confuses me, simple as that. Being born and raised in Florida made me think that December is winter and July is summer. I have been proven wrong aready, at 50 degrees farenheit in July, a sweater (even if it is just light) is better than nothing. Line the bottom of your purse with it, or keep your water cool by wrapping it around it.
Chap Stick
Gum
Map of the City - When (not if) your phone dies, and you have already used all of the extra battery chargers life, make sure you know how to get home (or to a Mcdonalds to charge up again) by carrying around a tourist flag, better known as a map. Just dont wave it around or open it all the way up in the middle of the sidewalk, no need to draw unwanted attention, or get in anyones way.
Motrin
Glasses
Sun Glasses
Hand Sanitizer - Always make sure to wash your hands whenever a possibility, but for the times a sink is unavailable, this could save you from ruining the whole trip with a cold or the stomach flu you caught off of a door handle.
Water - You have to pay for it everywhere you go, so save a little money and bring your own. When it is empty, refil the brita bottle from a sink or bottle you get from a market, and the filter will clean the water of harmful chemicals as you drink.
Handmade Language Guide - Ok it dosent need to be homemade, but I have a handy-dandy graphic designer who makes things like a language guide for fun. Any small pocket sized book will do!
Snack
Headphones
Flashlight - For when the night sneaks up on you, and now you cant find your keys at the bottom of your purse.
Agenda

Let me know if you think I should add something to my purse collection! I may need to change it to a backpack soon :)

Whats in your purse?