I got my iMac 3 years ago and I'm loving it! Still fast and I won't be replacing it unless there's something wrong with it.
I buy computer out of necessity instead of want, really. Before that, I was a PC girl as well, since apple was unaffordable for me. Saying that, I still have my Sony laptop, which is around 10 years old now. It's still working, it's on Windows XP, but, I'm pretty sure, it'll be soooo slow or dead if I try to scrap with it!
