I have split my RF through a passive splitter, so I can get RF into the tv, video and stb. It works OK for most of the freeview channels, but some of the muxes (the Hits and TMF etc.) have a slightly low signal when split, and occasionally break up. I'll get an RF amp soon cos I'm expecting a Tivo from Currys
I've got a 6-way S-video and composite switcher from Maplins, a Scart switcher from Argos, and a 5-way Scart parallel block. (4 games consoles, VHS, DVD, STB). It's a hell of a wiring nightmare, but it does most of what I need, except that the STB is only in composite. If I had an STB with 2 Scart outputs it still wouldn't really help, cos the T.V. only has 2 Scarts.
The system has slowly evolved and I rewired the whole lot again today! I love it...
When I get the Tivo, I'll probably run the STB straight into that, and get a second STB. Aaarrggggg!!!