September 2006: Bought my first Mac, a 20" Core 2 Duo iMac.
February 2007: Bought my second Mac, a Core Duo BlackBook (refurb)
May 2007: Received a 15" PowerBook G4 from work.
August 2007: Work replaced PowerBook with MacBook Pro Core Duo; I replace my white iMac with a Core 2 Duo Aluminum iMac (third personal Mac purchase)
November 2007: Work replaced buggy MBP Core Duo with MBP Core 2 Duo. Also bought an AppleTV, which is sort of a Mac.
So..I've bought three personal machines in 12 months, and had three work machines in 6 months.