Hehe Nimitz ... enjoy the heat .... I was born and rasied in San Antonio .... Eat some Enchiladas Verdes and go see the Jim Cullum Jazz Band

(they play nation wide on NPR from time to time) And enjoy the NBA champs ....
On subject why hareware firewall...most cable modems operate as NAT's and "routers" in thier own way spliting your data apart from the stream. Security is a good idea with cable as it's traveling on an analog, multiplexed line. (i.e. channel 3[KMOL NBC] - 72 [sci-fi]) are multiplexed signals; data is split in this same manner. So you have alot of other people on the same line as you. People that are at the Mac layer... good reason to have hardware firewall ... hope that explains. DSL is more secure, speacking in this reguard.
Enjoy San Antonio, Try Panchito's for mexican food

....Austins a good place to have fun too, about 50 mins away.