"Eastland-Fairfield Computer Support Services, this is Andrew speaking, how may I help you?"
I've answered my phone incorrectly before, but it's rare... but my greeting depends upon the time of day & what caller id says.
For example, if one of my associates calls me at 3 AM... it's something like "This had better be important..."
If a friend calls, it's "Why are you calling this late? Are you OK?"
If my parents are calling, it's "Satan here, what in he11 do you want?"