I have used both the Flybird (below/left) and Bowflex (bottom/right) adjustable dumbbell sets.  For home use, where the set does not move around much, I recommend the Bowflex set (and the set with the rack is a good idea).  They are a little more expensive, but much easier to adjust.  For a traveling trainer I recommend the Bayou set because it is more durable- the plates are metal.  They are slightly more difficult to adjust.  I use a hook-and-eye strap to secure the base to the weights when carrying them.

This set of Bodylastics equipment ("super heavy 31 pieces")  is ideal for a traveling trainer.  Lots of equipment in the bag to rotate and prevent wear-and-tear (or quick replacement from loss).  For a home gym, this is overkill, a smaller set will do.  The FitCord "Brute" (below) has lots of equipment included, but does not have as many extra accessories.  These accessories are not necessarily "missing" but definitely not needed for regular use.