For me it'd be hard to break it down in the first mannor, I've always had lots of consoles and I tend to play most of them on a semi-regular basis, but I'll give it a try based on years.
1988-1992 ~ NES only (ages 3-7)
1992-1994 ~ SNES, Gameboy, NES (ages 7-9)
1994-1998 ~ SNES, Genesis (ages 9-13)
1998-1999 ~ SNES, Playstation, Genesis (ages 13-14)
1999-2002 ~ Playstation, N64, Gameboy Color, SNES, Genesis (ages 14-17)
2003-2004 ~ Playstation 2, Gamecube, Playstation, Gameboy Color, Dreamcast (ages 18-19)
2004-2005 ~ Playstation 2, Playstation, Gamecube, GBA SP, Dreamcast, Genesis (ages 19-20)
2005-2008 ~ Playstation 2, Playstation, PSP, Gamecube, SNES, GBA SP, Dreamcast, N64, Genesis (ages 20-23)
2009-2010 ~ PSP, Playstation 2, Playstation, SNES, Sega CD, Dreamcast, Gamecube, Saturn, N64 (ages 24-25)
As for systems owned in order of total enjoyment...
Playstation > SNES > Playstation 2 > PSP > Gamecube > Dreamcast > Sega CD > Genesis > NES > Gamecube > Saturn > GBA SP > N64 > GB Color > GB
