So, most everyone should know about the bonus CD soundtrack that's to be included with the upcoming Collector's Edition version of the game. But it looks like Suleputer's set to release the official two-disc Original Soundtrack (CPCA-10201~2) on 2/25/09:
I'm delighted that it's getting the two disc treatment, but I guess it would have to be if they're to accommodate all of the music. We've got the SFIV-specific level themes, themes for the four new characters (Abel, C. Viper, El Fuerte, and Rufus) and then, from what I can tell, remixed arrangements of all the returning characters from SF2. I'm assuming, too, that the console-exclusive characters will also have their own arrangements, but the jury's still out on that one.
Personally, I'm really digging the music I've heard so far. The Snowy Rail Yard Russian stage is particularly catchy, and I'm loving the new remixes for Zangief, Guile, and Sakura. The Volcanic Rim stage theme, which is used here for the latest trailer (it starts about one minute into the video), is my favorite so far.