I was about 11 or 12 when it was confirmed that we'd appointed Kevin Keegan as manager, that was ridiculously exciting for me, and then Keegan himself went and equalled that when he signed Anelka! All I had known up to that point was shit managers and shit signings (bar Kinkladze).
Robinho is up there as well, purely for the SSN midnight deadline stuff.
Tevez for the obvious
That summer when Sven swooped in and signed about 35 players!