Married to miles,
As a former airline sales guy, I have one piece of advice: if your travel plans are mostly at Christmas and during summer, I presume that you are paying for these tickets yourself. In that case, you get nothing out of these frequent flyer programs. Instead, I would hunt down the cheapest fare I could find- probably via a consolidator.
If going to Europe in summer, consider the following:
Icelandair- cheap and you can get a very inexpensive stopover in Reykjavik. You'll save yourself a bundle.
Royal Jordanian ORD/JFK-AMS
Kuwait Airways JFK-LHR or ORD-AMS
Pakistan Intl. JFK-MAN
Biman Bangladesh (OK- this one might be pushing it)

However, if going to Europe in winter, then it doesn't matter who you fly- everyone is cheap!

Hope this helps!