On Tue, 26 Jul 2011 21:42:44 +0100, Gareth wrote:

Self-Drill Plasterboard Fixings, metal and plastic

Seem to work, not used them myself but have found a few here. Alright
for light loads like a picture...

Spring toggles

The toggle falls down the void should you ever have to remove the
screw...

Metal Plasterboard Anchors

I like these when set they spread the load of over a reasonable area
of plaster board. The stay in the board when you remove the screw.
Take good loads.

I imagine that plasterboard itself isn't very strong ...

Depends on the direction of the load. It's pretty good in compression
but weak in tension. So things that are pulling will make it bend and
over time deform permanently(*). If you can arrange the fixings so
the load is down the PB, ie it's trying to shear the fixing rather
than pull/push it through the PB it's surprisingly strong.




These things also seem to be classified as light, medium and heavy with
little indication of what is considered light, medium or heavy which
doesn't seem very helpful.

Rawplug give a maximum load on the packaging as well as light medium,
heavy.

would you trust a couple of Rawlplug Unos to keep a bathroom cabinet on
a plasterboard wall?

Donno not used 'em I have a stock of yellow, red and brown plugs and
metal wall anchors for use in PB. I'd use the metal wall anchors
simply 'cause I have 'em and know how they behave.

(*) 9.5mm plaster board used with normal ceiling joist spacing will
sag under it's own weight between the joists.

--
Cheers
Dave.