It's cute but Flash for navigation is pure poison because many browsers don't support it. Most notably Apple iPad, iPhone & iTouch do not support Flash. How will those users navigate your site?
For all practical purposes, Flash is dead as a web technology except for gaming sites and special device apps.
See Adobe Edge
Alt-Web Design & Publishing
Web | Graphics | Print | Media Specialists
I have to agree with Nancy with her persective.
It *IS* very wise for you to aim for "responsive web design" as it is more reasonable, feasible - as it is increasing better ROI for clients and more pleasant experience for web browsing experience for consumers (including virtually all kinds of platforms: smart phones, tablets and desktop).
Have a research and dig further on topic "responsive web design" concept through Google... and right here on Adobe as well.
Thus, you are encouraged to dig further on responsive web design. Just do it!
But not only Apple, most mobile devices don't support Flash. Think of it as preparing for the future.
Flash has a place. But as Nancy said, not navigation. You want everyone to be able to move through your site. In fact, for slow connections--not everyone has hi-speed access, Flash can slow things down.