I don't think it's absurd to bank miles for a trip a few years out. I have a lot of miles in the bank. I won't be able to use all of them very soon, but I'm not worried. True, there's a small chance they might not be worth much when I get around to using them, but in the overall scheme of things that's not the worst thing that could happen to me.

I think your AmEx decision should depend on whether or not the extra benefits are worth $395 a year to you. I dropped my AmEx Platinum a few years ago because they weren't and have saved a lot of money that way since. That's a personal judgment call, though. They weren't worth it to me, but that's not to say they're not to you or to anyone else. All I'm saying is not to keep that card for the mileage flexibility. There are cheaper ways to get it.

Two of those are:

1. Diners Club. It's accepted in more places (since they started co-branding with MasterCard), gives you primary (not secondary) insurance on car rentals, good CS, can transfer to AA (AmEx can't), costs $300 less per year and often has good transfer promos (50% bonus for BA transfers every summer, for instance). Downside: 5% fee for transfers, payable as cash or miles (takes 2,095 DC miles to get 2,000 airline miles).

2. AmEx Starwood Optima. Accepted everywhere your AmEx Platinum is, free for the first year and cheap after that, goes to AA also (regular AmEx doesn't) and a 25% bonus on mileage transfers if you move 20,000 at a time (get 25,000). Downside: you still need a Visa/MC for places that don't take AmEx, but you've got those.

BTW, if you want a DC, ask someone here (it can be me, but the important thing is to find an FTer with a DC) for a referral number. Doesn't cost you anything, gets the referrer a few miles.