As much as I love SoV, I have to echo (hah!) the people who picked the GameCube/Wii games (a.k.a. the Tellius games). They're both fantastic games, whereas all the other "eras" have at least one I didn't enjoy as much (3DS has Fates, GBA has Sacred Stones and Sword of Seals), and while I like Shadow Dragon and New Mystery, the Tellius games are just flat out better than those two in my opinion. I've never played anything before FE6, so I can't judge those games, but from what I've heard, they're pretty... mixed in their reception, so take from that what you will.