Get the Mac. I'm not sure if ferny has or has had a Mac, but the "Mac's don't crash" isn't rubbish. ferny, I am not attacking you here, I know sometimes things get lost in the written word, just wanted you to know that up front. I work with computers and networks for a living, and trust me-Windows machines do crash more than Macs. Now it can be said that since Microsoft has the majority of the PC market, this could account for the abundance of PC woes we all hear about, and that would be partly true. Macs do crash, but not as often or as hard as the Windows machines do. I have 3 Win desktops, 5 Win laptops(mostly put togethers, but two that I did buy), and two Macs(powerbooks). The powerbooks have both crashed, for lack of a better term, but I didn't need to spend hours trying to recover from it. No need to reload the OS. The Windows machines however, are a different story. At some point in time I have had to reload each of them at least once. I do the regular maintenance on them, but sometimes that isn't enough. I think the fact that Apple makes both the hardware and software to specifically go together is the biggest reason for the stability. Microsoft makes a product that really isn't designed for one brand of hardware and that seems to be the biggest problem.
Never the less, pianoman12 asked which we would choose, and I choose Mac. Windows is a very good platform, and tradionally has been the cheaper(price wise) system for beginners to get into, but the mini is now a viable option. Don't forget that the mini doesn't come with a monitor, keyboard, or mouse. If you already have them then no need to buy them. Remeber though, the need to be USB.