Luckily, my balls dropped shortly afterward, and a few years ago, I picked up the DVD of HEAT and gave it a watch. I couldn't believe how amazing it was. HEAT is truly a modern masterpiece, and is maybe the definitive cops & robbers film of our generation. I think HEAT is every bit the equal of Pacino & De Niro's finest work- and, sadly, one that neither has equaled in the years since.
It really is a flawless film, with Michael Mann making a film that manages to work on so many levels. Everything about is is perfect. The acting, not only from Pacino and De Niro, but even from Val Kilmer, Tom Sizemore, Ashley Judd, William Fichner, Diane Venora, Ted Levine, etc., is perfect. The music is incredible, with not only a fine score by Elliot Goldenthal, but also perfect selections from artists like Brian Eno and Moby. Who can possibly forget the bank robbery sequence scored to Brian Eno's 'Force Marker', or the final cat and mouse chase between Pacino & De Niro with Moby's 'God Moving Over The Face Of The Waters', working it's way into the score- before exploding over the final credits.
Of course, the film also works as a kick ass action flick, with the big bank shootout on the streets of L.A maybe being the finest shootout ever staged on film (for realism, Mann had the actors trained by former SAS man, Andy McNab- supposedly Kilmer is bad-ass with a machine gun).
Lastly, and most controversially, the Blu-Ray has a note on the back cover station that this edition has content changes supervised by director Michael Mann . Supposedly, Mann decided to cut a few lines, here and there- all though put together, these only make up seconds of screentime, and I didn't notice any big changes, although one line from the 'she's got a GREAT ASS!!!' scene has been cut. Overall not a huge deal, but purists may object.