Cable the PCs, put a nice N-router for the phones/*books. Router depends on money, for a relatively low cost and good performance, I'd recommend Buffalo's WHR-HP-G300N.

Yeah, that could work well. If I get Virgin to setup the router right next to my competer then I can cable it in and let the rest of the house conect wirelessy. Seems pretty easy.

They would be called homeplugs, and were second on the list I gave...

As long as you have decent wiring these are as good as normal cabling, There's a thread somewhere round here about the by Kiss Kiss I think which should explain a bit more.
Cost wise this is a lot more expensive than using cabling, prices can range from £30 to £80 each depending on what max speed they are rated for etc.

also remember that the signal decays dramatically across rings so keep that in mind when you place the first one. most houses have a simple 3 ring setup, upstairs, downstairs and kitchen the the same for the lighting rings. some flats have less, mains/lighting/kitchen.
if you are spanning between rings, make sure the router and first "homeplug" is as close to the fusebox as possible

Not sure if this is of any help but you can always try Dlan Duos. Basically a wired wireless connection, it uses the house wires to run the signal through or something. I don't know my dad confuses me when he starts to talk about it xD

dlan duo is just a brand/type of homeplug

Just for info, but Cat5 cable is unbelievable cheap. 10p a metre.

20M CAT5e RJ45 Cable - £2.05 Delivered

Ahh never knew that :£