I absolutely loved Firefly the series. It was indeed unique, and had Joss Whedon's signature brand of humor that I came to love from Buffy the Vampire Slayer.
Serenity, whilst having an awesome story, just felt like a minimalist jump to the big screen. It is VERY enjoyable on DVD/Blu-Ray, or even the Playstation Portable UMD format.
I am eagerly awaiting getting Firefly and Serenity on Blu-Ray.