Thanks for all your suggestions. Especially ILTE_Miles for taking the time to explain the whole 9 yards..

Well I think will all options considered I am going to join both for now and redeem this flight on NW considering the 2500 join in and 2500 before 07/31. So in effect I will have about 7-8000 miles.. Which I think is a good head start..

I use AT&T so much that even if I dont redeem miles on CO with Midway I think I will be able to notch up enuf in 1 year for a roundtrip in US if nothing else...

Thanks again for all your suggestions.. Keep them coming if any more out there... Were really helpful