I would recommend the Mac Mini, great little machine and priced reasonably for a preminum computer. I have it for more than 3 years, still running strong. The only thing failed is the internal superdrive that doesn't work well anymore. These failures are very common and thankfully it's not that expensive to replace it, if you wanted to.
Mac OS X upgrades are lot cheaper than upgrading Windows, you save the money in the long run as well.
Desktops on the other hand like the Mac Mini is losing popularity and most people are going for laptops and tablets today. Macbook Pro is other good choice.