Quite frankly you can do about anything you want. You could just use Blink's firewall component (if you wish) and disable the built in one in Windows 7 or disable Blink's firewall component only. Obviously you can fine tune rules and things a lot easier in Blink's firewall, but if you don't want to bother with all the popups and such when dealing with firewall rules, turn it off and allow Windows 7's firewall to run.
I know on my Vista Ultimate 64bit machine, I have Blink's firewall disabled and I simply control what is being exposed to the internet by either setting my Vista firewall to "Public" or "Private".
The choice is up to you, but there is no problem with having both of the firewalls on if you choose to do so.