Pro Tools 7 has introduced many new and many improved features this time around. Below pretty much encompasses everything you will see:

• Region Looping-- An easy, new way to repeat one or more audio/MIDI regions and Region Groups.
• REX and ACID audio files can now be imported into Pro Tools 7.
• Support for dragging audio, MIDI, REX and ACID files directly from the desktop to the timeline.
• Quantize your audio regions to a grid or groove template. Sort of a simplified Beat Detective, but for audio regions.
• Compressor/Limiter Dyn III is now included with the new release of Pro Tools alowing for more control. EQIII also includes a new filter band-pass solo mode to help isolate and remove nasty noise in an audio track.
• Tool Tips feature gives descriptions of objects in Pro Tools 7 simply by rolling the mouse over the object.
• Support for dragging audio, MIDI, REX and ACID files directly from the desktop to the timeline.
• Support for dragging multiple regions onto a single track simultaneously.

Personally, I haven't taken the jump to upgrade, still weighing up whether or not it's worth it for me.