New to forums, need recommendation for wireless setup

[sneakyjackson]

I want to setup a home network

we have comcast cable internet 20/2 mbs

Here is what I will have access my network wired and wireless

Apple Tv wired
Ipad 1 wireless
Ipad 2 wireless
Itouch wireless
Two Iphone 4s wireless
Asus Laptop wireless
Lenovo Laptop wireless
Xbox 360 wired
Blueray player wired
Directv wired

Right now I rent the cable modem from comcast (same one for 3 years)
I need suggestions on these
1. should I stay with comcast pay 70 dollars a month for the 20/2?
2. what wireless router should I buy ( is a gigabyte router overkill?) I want optimum performance?
3. Should I get my own modem and ditch the rented 3 yearold comcast one?
4. Should I buy a cable modem, gigabyte router combo, instead of having both a modem and router??

Thanks I really appreciate all the help. I know I need an N router for best wireless output, but other than that kind of clueless. I have been looking at this router ( ASUS Black Diamond Dual Band Processor, Hardware NAT, 5 Internal Antennas, Fast Gigabit Ethernet and 128MB DDR2 Wireless Router (RT-N56U))