So far hasnt' interfered with anything esle. I have Visual Studio 2005, Macormedia MX suite, Office Xp, and numerous other apps. No problems yet. I love the free stuff but always try to check it our first. No loss of performance either.
It's great having a son who's a software developer, he gets all the corporate stuff so at least its within the license use. Mind you these new easier development environments really screw up my little brain.