I personally like DM. I have found that their Gold Card gets you into a lot of airport lounges. I see that you are spending a fair amount of time in Europe. Carriers like RyanAir and EasyJet have incredibly low fares so earning DM may not be the right choice if you are on a tight budget. Avoid Alitalia if you can. They are having a lot of union trouble and seem to be cancelling flights on a regular basis.

Kibison