A no of people have spoken about this, but it is amazing how many gems there are in just over a minute of this affectionate look back at 50 years of the series that can be missed if you don't look in a nanosecond.
1) The Doctor's Fez at 0.06
2) Sylvester McCoy's and Peter Davison's voices at 0.10
3) Peter Davison's voice at 0.20
4) Sarah Jane Smith's reflection at 0.32
5) Maple leaf at 0.34
6) Rose's voice at 0.34
7) Silence at 0.37
8) Racnoss behind Paul McGann's Doctor at 0.38
9) Bessie the roadster behind David Tennant at 0.39
10) The Golden Gate Bridge (reference to the 8th Doctor?) and the Tower of Rassilon at 0.42
And I am sure there is much more there!