I must have hit just before the Sophia/Sophie 'explosion' too. (1/12/2007)

as popular as everyone says it is, I have only run across two other little Sophie/Sophia (her age or younger) at various playgroups and stuff we've been to, and one Sophie who is 8. And I never had one when I worked daycare/preschool, nor has there been one in DS's class (he is 5)
but then again, if I named her just before the explosion....I became full-time SAHM when she was 4.5 mos. old

I also had the name Sophia picked out oh say 10-15 years before she was born. I *informed* DH that this was our daughter's name. And even though I tend to stay away from 'popular', I would have stuck with it even if I'd hit the craze.
and I'm going to have to say I vote for Sophia over just Sophie only because it gives her the choice to use either one at various points in her life...
Even DD, who is 3, is usually called Sophie but sometimes wants to be 'sophia'

I also like Isabel though and think Izzy is a cool nn....
But if you *love* Sophie, go with it. Though I still have to say I'd officially put "Sophia" on the birth certificate---giving you the freedom to call her Sophie and her the freedom to choose later. (And I just like the 'a' ending with Elizabeth better than 2 'e')