Staniloae is unequal, and even tends to some scholasticism at times. However, all three are significant and can be useful, so that, if my friend had already a somehow ‘scholastic’ nature, I would probably suggest to him Staniloae instead of Schmemann, if he had an encyclopedic nature, maybe I would give him Florovsky rather than the other two.
Sophrony Sakharov, although modern, is closer to the Byzantine tradition, which may work as an advantage or as a disadvantage, according to person and time. For the Byzantine tradition itself, the anthology and translation (in modern Greek) of Hymns written by St. Symeon the New Theologian transmits its highest meaning and aspiration, which is the most immediate and bold relationship with God a man can enjoy.
Many things can be learned from the Byzantine Icons, thinking about and with them, but even by just having them in the same room with us, if we come near them with devotion. The books of Lossky and Ouspensky on the Icons are useful too. For an example of reading an Icon, have a look at this post, what an Icon told me about Christmas and Easter.
In the end I would say that nothing can replace the live conversation with someone who knows what we want to know, a conversation one can have in the parish, or even at a forum on the Internet, but with the inevitable limitation as well as risk of how rare it is to find a suitable person for such discussions.
Cf. OnLine: Schmemann, A History of the Orthodox Church