@Stachetastic: I agree completely with boarder42 that $500/month on spending makes using a card worth it. I carefully chose the card for reward bonus that I would continue to use even if I never opened another one again. I will point out however, that if you buy most stuff at BJ's or a warehouse store, you don't get the 6% on groceries. I tend to shop at BJ's, Sams, Pricerite, and Aldi. Out of the 4, I can only get points at Pricerite and they're so cheap that I hardly see any benefit. (BJ's and Sams don't qualify as grocery stores, Aldi doesn't take credit) I DO get 3% on gas all the time, and that's where most of my bill credit comes from. I'm going to evaluate at the end of the year if I should downgrade to Amex Blue Cash everyday (no annual fee) or if the yearly cost for the Preferred is offset by my rewards. I think if you shop at traditional grocery stores often, you'll do VERY well with the Amex preferred, but if you shop at places that are considered "warehouse stores" for groceries, or places that don't take credit, I'd get the AMEX blue cash everyday (or whatever it's called that has no annual fee)
@arebelspy: I don't know whether I'll pursue this or not, but I have gotten some great responses and my question hasn't changed. Even if I don't pursue this, I still find it interesting to know we can probably plan an entire vacation by using credit cards prudently. In fact, kpd905 really had some good suggestions that I'll be discussing with my wife!