since they already released an Athlon 4, it kinda makes sense to me that it will be called Athlon 5 (Athlon 5 must be better than Pentium 4, right?).....either that or some variant of Athlon 64
i REALLY hope they don't come up with another dumb name (i don't really care for Opteron too much)
EDIT: yes, i know they said it would retain the Athlon name....but i'm sure they're going to put some new spin on it to make it sound better than both the old Athlon XP and the Pentium 4