Thanks for the help guys. I think my choice now is just between UA or CO's programs. One other factor is in the UK we have a United credit card:
https://wwwa.mbna.co.uk/apply/UKCCap...UK-33333-11694
that will earn me some miles. I don't think there is anything for Continental though? If I got this card I guess I could only earn UA miles though I couldn't like give them my CO number and get them to attribute the miles there could I?