This kind of thread must be a useful resource for law enforcement
The best hiding place is not in your house or room at all. A location or a friends house that's relatively secure, but only you know about it and there's no way anyone else could connect you to it.
A friend of a friend had a huge stash that stood up to a raid. He had many items stored in things like pens, a cellphone battery that had been hollowed out (not recomended!) and a flat screen computer monitor. Most of his gear wasn't serious illegal stuff, he was just hiding it from a junkie (the one the cops were after) flatmate who would sift through his room for anything, painkillers etc. when he ran out of his own gear.
One clever trick was some empty spirits bottles on a shelf as decoration. The bottles were opaque and empty, the drugs put in a small container covered with glue and stuck to the inside of the bottle, impossible to find or remove without smashing the bottle.
However if they are SURE you have drugs hidden, they will turn your house upside down, they'll unscrew and unbolt everything and look inside every possible cavity in your house and your body.
If the cops have sniffer dogs your screwed anyway.
Even then there's ways around dogs but i wont go into that