I just saw this thread and thought I'd voice my opinion. I owned a Dell in HS, I got a desktop about six years ago and still have it in my room at home. I feel that I was pretty good with performing maintenance on it and keeping it in good shape, but after a couple of years it definitely slowed down significantly. At this point it is painfully slow to use. I would not recommend Dell based on my experience with it.
I currently use a MacBook, and I have been very happy with it. My MacBook is just three years old, and I have had minimal issues with it and it still runs good as new. My parents bought me this as a graduation present from HS so money was not an issue in my mind. I have had a very good experience with this Mac (runs quickly, easy to use, no major issues).
I have thought ahead to my graduating college (money likely will be a consideration when I am buying my own computer) and was wondering what my next computer will be, so I find this thread very helpful