Just an update in case anybody cares (recognising that each and every person will have a different set of circumstances).

I've all but decided to stretch for 1K one more year with UA--mainly because that exempts me from change fees on award tickets. I will then BURN UA throughout next year (it will be a good year for burning as I have a patchwork RTW in C for 2 sketched out--but I anticipate lots of changes to those awards to get the right availability) and meanwhile begin switching my credit for revenue flights to BD for the reasons mentioned above. That should keep me happy (and fee-free!) in 2009 and have me qualified for *G in BD by Feb 2010 when I'll need it.

Thanks all for your suggestions. The one-way and cash + miles are really what swing me to BD over AC.