I use a MacBook with Parallels and have Windows XP installed.
I tell you the truth: It is absolutely amazing!
Unless you play high end games, the emulation is basically flawless. In other words, XP runs bassically flawlessly for me.
Plus, it is seamless. So I can go back and forth to Windows and MacOS. You have no idea how convenient this is until you have it. For example, sometime you have to reboot Windows because you installed something. So, reboot it. Then you can continue your internet browsing or whatever in MacOS. Awesome. Also, with Parallels, you can just shut it down and it will save everything exactly as you left it in Windows. So now you can shut off your computer and still pick up where you left off (you can shut down Windows as well normally if you want as well)!
Also, you get the best of both worlds. There is some really awesome Mac software out there, but Mac by itself is too limiting. But when you have both you have the best of both worlds.
Think of it as knowing two languages fluently in a bilingual country such as Canada. While one language is really dominant (English), knowing French is sometimes essential for the best service or to acquire the absolute best jobs (for example, a government job).
If you can afford it, do it.