I installed Raspbmc and everything is working fine except for the purple tint. (Also happening in XBian)
The Raspberry Pi is connected to the tv via HDMI.
The HDMI cable works fine when connected to my PS3. The RCA jack isn't working so I can't test with that.
Also, when Raspbmc is booting, the logo screen has a black background at the start but it turns purple near the end of the boot.
I took a video of it: http://www.youtube.com/watch?v=tYhnEPv-I44