Yes, most definitely.
I'm running Windows XP on my iMac-- have been since late 2007. Still runs smooth, and I haven't had to reinstall yet (knock on aluminum).
I haven't yet seen any virus jump from my XP partition to the OS X partition yet. Then again, I don't do much in the way of web-surfing on the XP side, and use Avast for antivirus. I use XP mainly for Cakewalk SONAR, a Windows-only digital audio app similar in scope to Logic Pro or ProTools, and it works well for that. Everything else-- web-surfing, iTunes, you name it-- I do in OS X.
Legal Disclaimer: I'm not a hardcore gamer by any means, so Your Mileage May Vary.