Snow is alright. The art is obviously it's strongest point however it also tries a somewhat different take on Batman's early years and crimefighting methods which is cool to see.
The other origins are
Batman: Mr Freeze this was released alongside Batman:Bane, Batman: Poison Ivy for the '97 movie however it also happens to be Paul Dini's adaption of the TAS origin for comics.
Batman Annual 1; the New 52 origin was not generally well received and removes much of what made the TAS version work, collected in Vol.2: City of Owls
http://ifanboy.com/articles/dc-histories-mr-freeze/
The best Freeze imo is th first arc of Gotham Central. Apart from that there's actually not many stories worth hunting down, stories where he plays a prominent role at least.