Well, that's just it. I haven't really made up my mind which airline I would take. I think I still need answers to these questions before I can decide:

How many points should I expect to use for 2 upgrades?
Which airline/program is the best one to use for this?
Do I need to purchase a full fare coach ticket for the upgrade or is there some way around that?
What airlines have easy ways to acquire points?
Is it really worth all the effort to gain points for the upgrade since a full fare coach is so expensive?