I have been collecting and reading lots of rules the past few years but I think I am settling into what I want for each period/genre. I originally thought I wanted lots of detail, but in practical application, it just does not seem feasible.
ImagiNation (Horse and Musket): Field of Battle
---Blackpowder and Carnage and Glory II are contenders.
Individual Skirmish: Flying Lead and the rest of the Songs of Blades and Hereos series
Squad/Team Skirmish: Force on Force and Tomorrow's War for Sci Fi
WWII: Flames of War
Ancients: Clash of Empires
---Hail Ceasar and Piquet are options
Space Ships: Starmada
Pirates: TBD (most likely SOBH variant)
Wild West: TBD (most likely SOBH variant)