I don't know about KF (I only fly on SQ, don't participate in their program) but I know that M&M is one of the programs with highest award availability. Not ultra-cheap, you've to pay for taxes/fuel on awards as well, but availability is higher. Also, M&M seems (not really officially, but you can find some reports on FT) to get some seats on SQ's premium classes that other *A members don't get. And given your main earning of miles will be flying C, there is absolutely no sense in putting them to KrisFlyer rather than M&M, as you simply gain almost double on the later. Even if KF is somehow a bit better at getting awards on SQ metal, you'll have much less miles to eventually get those flights. So I would definitely go towards M&M, making FTL this year, then SEN next year. But if other posters would think otherwise, I'm more than glad to be correct on this.

Hi Shymere, welcome

Well, the thing is, Paris is NOT a *A hub, as France is Skyteam-country.

So I've to first assume you really want to fly with *A rather than Skyteam? Because in your case, Skyteam MIGHT be the better option, especially when you can choose full-earning economy fares.

But anyway, if you would go with *A, for the transatlantic flights you definitely want to stay on any European *A, as their product is quite a bit ahead of that from North American airliners. You might even route yourself over New York->FRA on SQ - for that segment, their Y costs aren't that huge, and if you can buy full fare anyway, it won't be too much of a detour, as you would have to fly over FRA or ZRH anyway. So, it's either LH or LX via their hubs or SQ via New York/FRA. Other options will be quite a massive detour as much I know. Of course you could also choose any US-based-carrier, but from all I heard around, their international Y product isn't much to write home about (neither so is LH or LX, but comparing, they're probably better - otherwise, SQ will be the only choice for semi-comfortable transport)

Anyway, it doesn't really matter which metal you select, but this is about which program you'll put your miles into. Here, the US carriers are probably better - as you're going to have some transcontinental flights, where US carriers still give out some free domestic upgrades (I'll never understand the concept behind this, but that's apparently how things work in the US) - for their own elite customers. So you might want to become a top tier in the program of your prefered domestic carrier. Now, while you get free upgrades with this on your domestic lounges, the US carriers WILL NOT let you into their lounges, even as super duper elite. Another weird US-anomily, but things are as they're. So, you simply need a *G non-US card, and you're allowed in. Don't expect too much, lounges in the US are generally crap, and I mean crap compared with FRA C lounges

As you won't have THAT much of flying, I suggest you make an easy *G on A3, where it needs only 19k miles, then you barely have to put miles into their program, but can enjoy full *G advantages including lounge access when flying US domestic. And it's the quickest way to *G anyway. After you've achieved it there, try to get Elite Status on any US-program. After all you're located in the US, so signing up for all those credit card stuff and getting tons of free award miles will be easy as pie

To cut it short:
A3 *G first
Whatever US program you think their metal you'll be flying for those long transcontinental flights (United?)

But I guess some other posters located in the US might know much more regarding US-domestic issues..