I originally went to university for Computer Science, but I got fed up with all the abstract mathematical junk, and really wanted to get my hands on something concrete.
After dropping from CS, I was thinking of moving in a more artistic direction (graphic design). When I looked over the tuition costs one last time, I realized that for all the money I would blow getting a degree that probably wouldn't get me a job, I could spend probably half as much tinkering with electronics allowing me to invent something that was interesting to me.
Ultimately my love is music, and no matter what education/hobbies I may have, I'll always want to do music in the end. The arduino is a blend of all the things I have an interest in (programming, hardware, electronics), and has applications in something I love (music).
I suppose you could say it has and will change my life.
I just look back on my early education, and wonder how my life might have been different if you could have something like this for 50 bucks in those times.