I've spent millions per year on cards (business - I wish it was personal!) and have some insight. One thing not mentioned much in the advice above is diversification. With $1MIL to spend, you don't necessarily want to spend *just* on the single card that yields the best value - you'll want to mix it up a bit.

As your "go to" card, you have it right with SPG. The points are generally worth t he most to people, and with the 1.25 to 1 point/mile conversion ratio (sometimes greater when concurrent with promos), you'll inherently have access to airline miles from many carriers when you want them.

If you'd like to obtain *status* - which greatly enhances the value of your points/miles - there are two cards to consider:

1) The Amex Delta Reserve card. If you spend $60K *on the nose* (don't go much past, as the return diminishes greatly), you'll get 90K Skymiles *and* 30K EQM/MQM miles towards status. You'll also get a BOGO companion certificate (good for first class, too) *and* SkyClub lounge access/membership. There is a $500 annual fee, but these later two perks alone are covered by it. Even better, it's almost a given that there will be a promo sometime during the year where you can register and earn extra miles on top of the 90K RDMs... sometimes it is even a double-miles promotion (like last fall) where you could have kicked it up to 150K SkyMiles for that $60K spend. That's 2.5 miles per dollar spent. Impossible to beat with other cards. Here's where it gets really pretty.... get a second card of the other flavor (there are two: business/consumer) and do it again. Spend another $60K. Now you'll get twice the miles, but more importantly, another 30K EQM/MQM status miles. This will bring you very close (and past, in the first year) the Platinum Medallion level... Delta's *second highest elite status*. If you can spend your $60K 8 2 = $120K quickly, do it all early in the year and you'll need to do it only every *other* year, if you'd like, as status earned in one year carries through all of the current year plus the next. You can alternate years and still maintain the status. You'll hear many people complain incorrectly that SkyMiles are "worthless", but they're usually lumping international and/or non-status redemption with everything else. If you have status and redeem domestically, you can readily use 25K miles to get *first class* seats, even just days before departure, with no booking, bag, change, or cancellation fees! You can't beat it anywhere. As you seem to travel on a discretionary basis and just a few times a year, this could be a great match for you. Maybe you'd step it up to ten or so 25K redemptions per year (250K miles) that would mostly be first class and give you tons of flexibility for change, no fees, early boarding, the works. I do this readily and it's the next best thing to having a private jet... seriously.

2) The Chase Marriott Premier Signature Card. Others will knock the value of Marriott points versus SPG points per se. They're correct to do so. However, they are ignoring the status aspect. Similar to the Delta Reserve card, the Marriott Signature card allows you to earn upper elite status via spending alone. You get 15 elite qualifying nights (EQNs) annually just for holding the card, and you get another night for every $3K you spend. As with Delta, status earned one year is good that year and all the way through the next. Therefore, you could spend $180K on the Marriott card early every *other* year, earn 60 EQNs plus the 15 bonus EQNs, and maintain Platinum (top level) status. Of course, if you stay a few paid nights and/or do some promos, you might not need to get the full 60 this way, so maybe you'd need to only spend $120K to earn 40 EQNs, for example. Having Platinum will really enhance your hotel stays beyond what you'd get with lower-level status for other programs. Even if Marriott isn't your favorite brand, it's worth doing if you can utilize a dozen or more nights a year.