Two :
Sony DSC-F707 and DSC-S75
Why do you need two ?
So that you can take one to any situation that you would not have with your main DC.
Say, I would not take my F707 to the beach but I would with my S75.
If there is a deal (and there will be), I would exchange my S75 with something smaller or different.
Oly UZI (C2100UZ) seems nice with 10X with Stabilization (sp?)
or Sony U20 maybe ?