Hi Flavius. I'm in NH too. I have a 2010 GT with bluetooth and no USB. There is an audio input jack though. Check this thread on ipod integration. Looks like there's a $10 amazon solution and a $200 mazda solution. I think the full mazda integration allows steering wheel control eg fully integrated, vs the audio jack. Not sure though.
USB is still not really standard on many cards, but its gaining popularity. Bluetooth audio is still the easiest to use once setup, and more will probably move on to it before making USB a standard feature. Like mark said at least there is a Aux Input jack. Using high quality (320) mp3's even flac/lossless will help the BT Audio sound at least as good as possible, but it won't beat a digital connection.
Interesting device. I got myself a 12v charger for my iPhone today. It also has a USB port, so I should be able to charge my iPad at the same time now.
It's one thing I've noticed about Mazda. They have the cool features but they aren't as cool as they should be.
Bluetooth and aux in stereo but no USB or SD card
Memory seats but no memory mirrors
Passive entry but a key replacement rather than a push button
Bi-xenon headlights... not auto leveling...