Tamagotchi V4:
Really fun games, your tamagotchi can get a job, earn skill points and connect with V1, V2, V3, other V4s, and even V4.5! I love it!
V4.5: Doesn't sound as good as V4, V4 is absolutely awesome, while V4.5 sounds nearly absolutely awesome. I don't have one because V4.5 never came...