Sky you can (if you wish) run all your own cabling without too many issues. It's simply good quality satellite grade coax (WF100 twin the thicker stuff, or WF65 twin which is the thinner stuff). For a simple installation each recorder box requires two direct feeds from the dish. You could most likely prewire from a likely dish location to where you want the box and the Sky guys wouldn't bat an eyelid so long as the cable was up to the job.
Virgin (V+/TiVo) works a little differently. Essentially it's an internet connection over coax cable. A single cable delivers the data feed so that the box can record one channel while watching another, which is what Sky+/Sky+HD does. TiVo can record more than one channel at once. It has this "predictive recording" thing where it takes your viewing habits and makes recording of similar types of programmes.
When it comes to a Virgin install there's quite a bit of debate about what cable is used. I'll come back to that in a minute. There's also mention of the installer adjusting the signal level to take account of the load down the street and in your home. It's definitely true that the signal has a tolerance range so just DIY splitting and extending will probably cause some signal loss problems. The other thing is that because the signal is data in nature then I personally would avoid sending through a house distribution system. Unless someone here can point to info to say it would be fine, my guess is that it wouldn't mix happily with Freeview/DAB/FM signals in a typical house distribution system.
The cable Virgin use for their installs is a triple shielded coax called Webro HD100. The spec is very close to Webro WF100 - a good quality satellite grade coax - but that cable has only double shielding.
Cutting to the chase, all of the whole house TV installs I have done have been based on one or two Sky boxes plus Freeview. That tends to be a solution that most find works well.
The lowest cost solution to install is a single Sky box (usually in the living room) which is also connected to the roof aerial. The RF2 output from the Sky box feeds back to an aerial distribution amplifier. Each feed then goes off to the various rooms in the house. At each TV location there's a Sky Magic Eye. This lets you take a Sky remote control and change Sky channel and do all the play/record/live pause activities just like you're sitting in front of the box in the living room.
There are some caveats.
* The distributed signal is RF, so it's not as clear as watching via a HDMI connection on the main TV. That also means you don't get the full benefits of Sky's HD channels on the other TVs.
* Sky can only show one thing at once. So all the TVs have a window on what is being watched on the Sky box. IOW you can't watch Sky Sports in one room and Sky Movies somewhere else at the same time. Nor can one person watch a live channel while someone else watches a recording. If you want that you need multiple Sky boxes, so Sky Multi-room is your answer.
* Your other TVs must have a TV tuner capable of receiving the older style analogue channels.
* You have to work out as a family who has control of the Sky box and when. That's easy to do if you have one remote assigned for the other rooms. Whoever has that has control. The rest of the house then watches either the same thing off Sky, or something different from Freeview, or something from a locally connected Blu-ray player or games console or streaming box.
You can do something similar with Virgin but it is more complex. The Virgin TiVo box doesn't have an aerial out for a start, nor does it support the Magic Eye idea that makes a Sky box so easy and inexpensive to control remotely. There are ways round these limitations. But is does mean more boxes, more complication and a bit more cost.
There are then ways to build on top of this basic framework. Additional Sky or Virgin boxes can be added so two (or more) channels can be watched as well as Freeview. It's possible to distribute HD quality via HDMI cabling or network cable with Baluns. I'd also strongly consider wiring network points for each TV. Streaming is becoming very much a standard feature. Smart TVs make it easy to use catch-up services such as BBC iPlayer/ITV player/4oD/Demand 5. They'll also play content off a connected PC or NAS drive.
There's probably more info here than you were prepared for. Have a read over, do a little Googling, then perhaps come back if you have further questions.