I have been using the free version of Zonealarm with Broadband for about 18 months and am more than satisfied with it ~ and I'm a bit paranoid about security! (even though a hacker probably doesn't want my holiday pics etc)
No you won't have to reconfigure when you connect to Broadband. Any program that requires access to the internet shall request it and you can decide to allow once or permanently. If you upgrade a program Zonealarm will ask the next time it tries to connect to verify you are still happy to allow the connection.
Dead easy and free!