Mine is probably infantile compared with most here, but I've been happy with it. I carry the Citi Dividend MC for the 5% Gas/Grocery/Drugstore and for the occasional transaction where they only accept Visa/MC (I don't spend much per year, and 1% back is better than nothing). I carry my Discovercard usually for whatever Get More promo they are running at the time considering it is usually something that is applicable to me. This also helps me get to the limit I need to start earning 1% on my "other" purchases, even though I rarely use it for that. The other card I carry and use regularly is the AMEX Costco card; pretty much for the 3% back from restaurants, 2% for travel (not that I do much travel), and anything that isn't covered by the higher bonus cards that I can use AMEX for (again, 1% is better than nothing).

4 cards I hand-picked:

Chase Cash Plus Mastercard: 5% gas stations, supermarkets, drugstores and 1% everywhere else (don't use this part).

AT&T Universal Rewards Card: 5X ThankYou Points at gas stations, supermarkets, drugstores, and AT&T purchases and 1X ThankYou points everywhere else. I like this card because of the 25,000 points for domestic airline tickets and can book as late as 14 days in advance. Combine this with the ThankYou network where you can earn 1-40 thankyou points per dolalr spent online, in stores, and on gift certificates at participating merchants and I can quickly get a free airline ticket. (ThankYou Network points post slow however (about a 2 month lag from actually spending with their particular partners). Also comes with calling benefits which I have not used yet but are free of charge and make a decent addition to the card.

World Wildlife Fund Card: Donates 1% to the World Wildlife Fund and in addition you have your choice of various rewards programs (I used to have free cash rewards but now have cash plus although I have heard other say that only free cash rewards is available now). So in essence I get 1% back and my charity of choice gets 1% so I get 2% back. They also have other charities with payouts from 0.5% - 1.0% before the rewards program is added.

Hilton HHonors AMEX Card: 5 Hilton HHonors points per dollar at gas stations, supermarkets, drugstores. US Postal Service, Restaurants, Hilton Hotels, and wireless phone bills and 3 points per dollar everywhere else. I use this card strictly for dining and Hilton Hotel purchases. For 125,000 points you can get 4 nights at any category 5 or 6 hilton hotel subject to availablity. These rooms usually go for about $300 - $400 a night so that is about $1200 - $1600 saved. Slightly better than the 5% CashBack card if greater than $1250 but since the CashBack cards don't offer 5% on dining except discover I have chosen this card. Also comes with many of AMEX's great services like Assured reservations and warranty extension etc.

My cards:

Citi Dividend Plat Select
GMAC ATM/Debit Card (no fees for ATM withdrawals/reimburse $6 for banks that charge you fees on their ATMs)
AMEX Gold Rewards Plus
Chase PerfectCard (I want to get convert this to Cash Plus...the clone of the Citi Dividend Plat Select).

Its stored in a diff area of my wallet mainly because if I put it down somewhere I'll forget where it is later and it'll bother me to know always know its with me and not being used. Its fine.

New Chase 5% cash rewards for grocery and drugs
RBS 1% Cash Back For everything else
Capitol one Card for business related purchases
And a condom from 1985

Am I the only one who doesn't carry all of his credit cards with him?

I want a thin thin thin wallet so it doesn't bulge out and result in a pinched nerve after sitting on it for a long time.

So I carry:

1. Chase Reward Plus for gas, food, groceries
2. AMEX True Rewards for Costco
3. ATM card - just in case I need it

I have 4 other cards that I leave at home and use on occasion.

Way too much. I have:

-Visa Debit Card for ATM
-Citi Dividends for Gas/Drugstore/Groceries but currently using BT offer
-Citi PremierPass because I am supposed to get a $100 gift card for it
-Chase Perfect Card for use because I cant use the Dividends card right now
-AMEX Blue
-AMEX True Earning for CostCo
-A couple Best Buy gift cards/store credit
-Metro SmartPass
-Rebate Check from SanDisk that I havent cashed and is getting a bit worn out

Almost all of them I can blame directly on FatWallet.

-AMEX Platinum Card
-MBNA Worldpoints
-Citi Diamond
-Check Card

Strategy Cards:

Discover Restaurant - Try to use for all restaurant purchases, but 30% of the time restaurants don't accept Discover anyway.

AMEX Blue Cash- Use for businss expenses and tuition I am reimbursed for. Good b/c I get 1.5% back on purchases over $6500, and I will probably put 20K on it this year.

Chase Cash Rewards - Use for everything else (gas, grocery, cable bill, car insurance, etc) and PIF. Everday purchases get 5%.

Backups (in case using a BT, etc on main cards):

Citi Diamond Preferred- Got 10K points for opening ($100 gift card). Currently using for BT and will convert to Citi Dividend when that BT expires.

SECU Scorecard- I keep this handy because is has a 7.99 FIXED APR on everything (purchase, cash advance, balance transfer). Plus, you still get points for BTs, and there are NO FEES for BTs or Cash Advances. It will come in handy if I ever need cash quickly. Also, if I ever need to make a purchase that I know I can't PIF, I can use one of my other cards, and then transfer to this card for DOUBLE POINTS and a decent APR.

Bank of America FInancial Rewards- Get $1 for every full $100 spent. No rounding. Can also use points to BUY DOWN your APR. Never tried because I have 7.9 fixed, but it is an interesting idea.

MBNA/Wachovia Worldpoints- Get BT offers often. Waiting to see what happens with BofA/MBNA merger and Wachovia starting up their own CC division.