Monitors and speaker stamds?

Blu-Tack soft adhesive and Moongel (used on drum heads), sold at music stores. Many reviews of each available.

+1 Blu-Tack for my Spendor D1's

I use IsoAcoustics Orea pucks.  A nice clean surface s required on both sides but they have suction cups on top and bottom and do a nice job of holding things in place.  It is also better to isolate your speaker from the stand than isolating the stand from the floor.  

They have a less expensive pro audio puck that is in black that is virtually identical in terms of performance but doesn't have the polished metal look.  

I have found that different speakers sounded best with different mounting methods.  My Harbeths hated being secured tightly to the stands and worked best on spikes or some other hard interface, while my Operas functioned best when secured tightly with a dime-sized piece of Blu-tak on each corner.  That said, if you have little kids or any other danger of the speakers getting knocked over, you should definitely use a secure mounting.  But safety aside for the moment, you should experiment both ways.