It took me some time to find these great apps, so I figured a mention might help others:
- Shift It enables easy moving and resizing of windows using the keyboard (expands the concept of Aero Snap)
- Afloat will let you keep windows on top, adjust window transparency and much more.
In case you’re wondering, they’re both free and open source.
Update 2014-02-03: The link to ShifIt has been updated and now points to the new repository on Github.