I have noticed the following behaviour.

If Minecraft is active or minimised on the taskbar, using Windows 64bit Home Premium. Spybot S&D stalls when starting up and the OS quickly spits out a (Not Responding).

I have been able to replicate this behaviour.

Windows 7 64bit Home Premium. Fully updated.

Minecraft - current version (1.2.4_01)

This behaviour was present with previous versions of Minecraft.

Just a heads up.