Using portable application on you HD.
Why I use portable applications on my HD:
They are permanent and stable. Indeed If I reinstall windows xp, All my program will be ready to use, I will not have to lose time to reinstall all my favorites applications. Since the settins are stored to a local directory, I never have to reconfigure preferences and options. Indeed xml or ini configuration are remanent.
They are small and effecient. I can install them on my other HD. My c: drive including windows and program files is only taking 550 meg of space. This allow my pc to have extreme perfomance. Portable application are the tweaker companions, because they allow you to futher speed up your pc.