There is a theory that faster clock speed "races to idle" quicker, but it has limits when the rest of the system is slow like the memory reads/writes. Too slow of a clock takes too long to finish any task and ends up using more power. I would just recommend regular default clock speeds since without undervolting, the cpu freq is only a small factor compared to other parts like 3G radio, screen backlight, and vibration motors, which draw a lot more current.
The Optimus V had some gps wakelock bugs that have been resolved in recent CM7 ROMs. A lot of phones probably have unintentional wakelocks, only in ICS have Google started to try to make it easier to detect them.
