I have two key rings:
1) Just our house key on a ring with a small tab that can snap into my purse. I use this when I walk to/from school and around the community (we can and do walk to many local places). I also use this when I drive our Prius because it has a fob only (no real keys of any kind) and that fob doesn't go on a key ring. It just sits in my purse or pocket.
2) Just a ring with three keys on it: house, mail, other car ignition; and the other car's door-opening fob. No cute key ring emblems or anything except those four items and the ring holding them together. This greatly reduces the weight and bulk!
I have a pub mirror hanging by the front door. It has a mirror, skinny shelf, and three hooks underneath the shelf. One key ring is on one hook. The other key ring is on another hook. My small purse hangs on the middle hook.
I do not have a separate wallet. Even when my child was younger, I have always had the types of purses with the wallet built-in. Makes it so much less bulky and I cannot lose a wallet when it is built-in to the purse.

More frugal, too.

My DD is 8 now, so she is responsible for carrying her own stuff and I carry my own stuff.
My purse holds:
wallet area
driver's license
debit card
AmEx card (serves triple duty - 2nd picture ID, Costco membership card, and our emergency credit card)
library cards (city, county, nearby city - all mine; DH & DD have and carry their own -- we go frequently these days)
my insurance card
DD's insurance card (different carrier; when it was the same carrier, I only carried hers and left mine at home; they were able to look mine up from hers)
a few gift cards and program cards (only the ones we use often; for any place that accepts just a phone number, we leave the card at home)
cash & coins
wedding picture
most recent school picture of DD
main purse area (small)
cell phone
camera (small Canon)
handmade salve (super handy first aid kit all-in-one)
hair elastics
sunglass clip for my glasses
ice arena card for DD's ice skating lessons (this is about to expire and it will be removed promptly when it does)
pen (sometimes, it often gets removed and not as often gets replaced)
That is pretty much it. I have an exterior open pocket on my purse and I use that space for collecting receipts or other items that need to leave my purse as soon as we get home. If I need to really hear my phone and be able to get it ASAP, then I put it in this pocket short-term. I prefer to have it in the zippered main purse, so it doesn't fall out on accident. I slide it in my pants pocket and put it on vibrate when I don't want it to ring, but need to know if I get a call ASAP. (These are rare these days, but have been important in the past.)
Near our front door is a tall bookcase. On one of the shelves is a wicker basket. I keep a wallet insert in one of the spaces of the basket. I keep my regular credit card, YMCA membership badge, less often used program cards and gift cards, and the library cards when they aren't being used so frequently in this. It is not seen, but it is convenient for me to add/subtract items from my purse as I am walking out the door when necessary. Behind the wallet insert are our coupons, which are organized. Anyone in the family can grab whichever coupons/gift certificates we may need. I put those in my exterior pocket of my purse (sticking out a smidgen on purpose), so I don't forget to use them. I can slide a simple snack into my purse for myself and sometimes DD (depends on what it is and how much other "new" stuff is in my purse for this occasion), but I have to carry a water bottle for myself. I have two Chico-style reusable bags that I keep in the wicker basket and will clip onto my purse when heading out for errands on foot or in the car when I know we'll be walking between stores. (I keep other reusable bags in both cars.)
When DD was younger (but after the full-on diaper bag stage), I carried a backpack purse. I could fit water bottles and snacks and single diaper with travel wipes and cell phone and separate (small) camera in my purse. This was between the ages of 18M and 3Y for the most part. I still use that backpack purse for specific places when we will be gone all day and don't want to carry a separate bag. I travel with it most of the time, too.
Before 18M, I used a backpack-style diaper bag. It didn't have a built-in wallet, so I used a single pouch with one compartment and one zipper. I folded bills in half and slid those along with our debit card and my driver's license in the pouch. Change got tossed into it, also, but got spent right away since there wasn't a ton of room.