Conde Naste Traveler Article
 

I sat down with Conde Naste's Traveler March 2006 and inside there is an article that describes the best cards for a traveler's travel goals. It also cites webflyer and flyertalk. There is a very easy table to refer to as well.

For me the best set up seems to be

get the Starwood amex
keep the delta amex
keep the AA m/c

It is worth the read. I can't say that it makes sense to me yet, but hopefully I'll get there.

C

Choice of airport in NYC makes a difference, too. If you are heading downtown, then EWR might be slightly preferable to JFK. If you usually head to midtown, particularly the east side, then JFK will be preferable. Choose your hub airline accordingly.

IMO the only reason to select CO would be for the free domestic upgrades (assuming you can get them) and perhaps to bank miles if you plan to fly their Skyteam partners to Europe. By contract, if you want to use your miles to upgrade those hellaciously long flights to Europe, the choice is clearly AA or UA. Also CO charges a ridiculous co-pay for many mileage upgrades (e.g. $400 one way), AA charges $250, and UA zippo (though the required fare class is higher).

In addition, be advised that purchased domestic upgrades on AA run $30/500 miles vs. $50/500 mi on UA. So if you want to upgrade LAX-JFK-LAX, it will run $300 on AA and $500 on UA. In general I have found it easier to secure an upgrade on AA than UA, but YMMV. Don't know about CO.

As for WN, the airline is great for short hauls, but probably not suitable for your situation unless you are travelling to the middle of long island, i.e. not Manhattan.

I agree with AA/UA are the best choices unless the OP would be buying business class tickets for Europe than CO may have a slight edge by the frequent Z class sales and AF.

If between AA/UA, I would say AA due to 3 things:
1. Challenge so you can build up status fast.
2. 1 MM / 2 MM includes credit card miels (for now) so the user can transfer his MR to increase total quickly and potentially even direct business spending there.
3. The upgrades are less expansive to purchase. UA has more upgrade instruments for top tier (SWU, CR1, 500 milers) but AA stickers are less expansive if the OP might be buying cheaper fares and upgrading.

Have done AA JFK-CDG and it was one of my best transatlantic in terms of service but I had an awesome crew on the way back. LH seats was slightly better than the AA seats but the champagne was definitely much nicer on AA.

Forgive my naivety, but what is "challenge"?