Here is list of most top selling Christmas gifts since 1929!!! My favorite ones among them all were; The Slinky and Teenage Mutant Ninja Turtles, I remember collecting whatever new version was just in.

2009: Nook eReader (Barnes & Noble)
2008: Elmo Live (Fisher Price)
2007: iTouch (Apple)
2006: Playstation 3 (Sony)
2005: Xbox 360 (Microsoft)
2004: RoboSapiens (WowWee)
2002-2003: Beyblades (Hasbro)
2001: Bratz Dolls (MGA Entertainment)
2000: Razor Scooters (Razor USA)
1999: Pokémon (Nintendo)
1998: Furbies (Tiger Electronics)
1992: Barney Talking Doll (Playskool)
1990: Teenage Mutant Ninja Turtles (Bandai)
1989: GameBoy (Nintendo)
1982: BMX Bikes (Schwinn Sting-Ray, Others)
1981: The Smurfs (Schleich)
1980: Rubik's Cube (Ideal Toys)
1977: Slime (Mattel)
1959: Barbie (Mattel)
1952: Mr. Potato Head (Hasbro)
1943: The Slinky (Poof-Slinky)
1936: Monopoly (Parker Brothers)
1930: Mickey and Minnie Mouse Handkerchiefs (Waldburger, Tanner & Company)
1929: Yo-Yos (Duncan)

Source