The Q9c is exactly like the Q9m minus the music Homescreen.
I use my Q9m as an mp3 player when walking around town at least three days a week. After installing TCPMP it's great for this.
I have a new Zune that I watch most of my video on now, but the Q9m saved me over Christmas when I was stuck at my parent's house because I'd loaded up a couple movies. You will need a converter (since I'm at work I can't remember exactly what I use), but it's an easy process. Again, as far as the player on the Q9m, TCPMP comes through again.
Finally, don't forget Pocket Nester.
I haven't tried using the Q9m as a modem.