Windows Movie Maker 6 (Vista Version) for W7
If you are now running W7 and don't care for WLMM, you can download the Vista WMM v6.0 (arguably the best Movie Maker to date) from this site
. When coupled with the recommended Rehan Shader TFX module
(a mere $15 shareware and well worth it), you can have a host of additional transitions and effects as well as chroma key and PIP ability. And the effects can be user modified if you can edit simple HTML script definition files.
WMM v6.0 has the conventional timeline and look/feel of the old XP WMM, but with much more capability.