That.
Of course, it really depends on what usage is done on the computer, but a 4 to 5 years old Mac is still a great, functional and reliable machine for most non-techie users.
+1
My GF has my 2006 1.86 GHz CoreDuo Macbook.
It's still very capable. My new MBP is not significantly better for day to day use. I imagine my MBP would be a lot better for gaming but neither of us does that.
I fully expect the MB to last another 3-4 years.
Prior to that she was on a 2002 700 MHz iMac. Actually still quite useable, though desperately in need of more RAM.