Aye I'm an ADSL man myself but I had to set-up a Virgin media Cable connection for a client last week so I got thrown in the deep end kinda!
As you already know Virgin supply you with a little black box that accepts the co-axle cable and has only a single ethernet port to connect one PC directly (nothing else, no USB etc so if your PC hasn't got a NIC you will need one unless of course your using the wireless).
I didn't realise that this cheap little box has no router built into it so I was left scratching my head when I plugged several network computers into it via a switch and only one of the PCs could connect to the web?
One quick phone call to tech support revealed that the little black box was in fact *not* a router and I would need to buy one from the sales-line. I then called the sales dept and they informed me they don't sell routers!
Anyway I dived down the local PC superstore and had a butchers at the Cable Routers on offer, ended up buying this one:
Belkin Wireless G Router
Part # F5D7230uk4
£38.76 inc VAT from Overclockers.co.uk here
I would have bought a Netgear if I had the choice but I was out on a job and had to make the best of it so picked up the Belkin and it did the job perfectly, literally plug'n'play. I haven't tried to use the wireless bit yet, I just linked several pcs via wired ethernet cable. The Belkin unit can accept 4 ethernet cables but I just plugged a switch in and off I went.
I'm sure most Cable Modem/Routers from a decent manufacturer will work just fine so the final choice will be down to you, good luck!