I have both consoles and overall I say the 360 is better. The online may not be free but you can find a year subscription for $40. The interface on the xbox has more appeal and it's more user friendly. I don't remember the last time I turned on my ps3. For me, the xbox controller is better overall. Mostly like it because it fits my hand better than the ps3's and the triggers are great for FPS and Racing genres. As for game exclusives for both consoles the only game that I would play for the ps3 is metal gear, twisted metal and little big planet while xbox has halo, forza and fable.
If you're more into playing with your friends online you should see which console they own too. Sometimes it gets boring playing with random people.
P.S. Xbox 360 mics > PS3 mics (oh wait.)