I have a netgear WGT624 and run 4 PCs, and 1 - 3 laptops off that. I used wired connections for all the connections, except 1 of the laptops. The service I'm on is 10 Mbs down, and 500kbs up. (10 Meg service from VirginMedia). One of the PCs runs P2P between 20kBs and 400 KBs. The P2P did slow up the internet access until the cable modem was replaced. I've had the netgear WGT624 for about 2 years and the only problems I have had with it are wireless.
The wireless problems were due to the number of other local wireless networks. Its been much better recently as many of them have gone. This is probably due to the fact that many students live in my area, and most have gone back home.
I would cable the PCs, the tivos, and the games console, and that would leave the 3 laptops and your phone over the wireless connections. If you are concerend about the load on the router why not invest in a cheap 10/100 switch. I bought a generic 16 port one of these for about £15.00 about 1 year back and it works fine. All the router does is provide the wireless and route the internet traffic. Swapping files and streaming video will be much quicker than over wireless.
You may find that the VoIP quality will suffer, as the traffic for these phones needs to be given prority. I would use the switch on the router for the VoIP phones, and the other switch for the rest of the wired connections. You should also be aware that each VoIP phone call will use about 10% of your upstream bandwidth, assuming you are using G711.
If you must have everthing wireless you could fit another wireless access point so some of the connections are one the router wireless, and the others are on the second access point.
Rob Murphy.