Get a Surfboard that will support the newest DOCSIS standard. The SB6121 is a good modem and will do as fast as Comcast can go for the next year at least in your area. I'd recommend a separate router since a modem and router together would have a higher likelyhood of totally putting you out of commission. At least if your router dies you could hook a PC to the modem.
Cisco Linksys is the typical recommendation. Anything new should suffice fine for what you are looking to do. I had a WRT54G for 3 years and it couldn't push more than 20mbps... Once I swapped it out I could burst up to 38mbps (I have an upgraded plan).