I hate a stinky, soaked sponge.  The best way to keep it from getting that way is to dry it out after each use.  This saddle sink caddy really does the trick.  It sits securely between the sink halves. Unlike a soap dish on the counter, it doesn't collect water thanks to the drain holes.  My sink is white so I bought the white caddy and you hardly notice it there.  It isn't obstructive or obtrusive at all. 

Pros: Great value, easy to clean, well made.
Cons: None