I'm not so sure about that. I was planning to get a Spyder but then I read reports about how the factory calibration was so bad that many of the units need calibrating against a known good unit before they're usable (otherwise you're just calibrating your screen to some arbitary, wrong, target). I'd like to get the EyeOne Display 3 but they're quite a bit more expensive so I think I'll just have to do without for now I've done a reasonable job getting the gamma, brightness, contrast and colours looking OK without (it helps that I can turn off individual colour guns on my TV) but I know once I'm able to properly calibrate it I'll realise how off it currently is.The Spyder is a "low-cost" consumer option. They vary great in quality. But they are better than nothing!
Regarding setting deinterlacing in the profiles, is that not unnecessary considering the GPU will do that (on the GPU so reducing the CPU load)? I use ATI which I've set to use Vector Adaptive deinterlacing in CCC.
Regarding the display output setting in the GPU control panel, I think you have to be careful if you use the PC to play games as well as watch video, in which case you probably need to set it to display full 0-255 RGB and then set your video settings/profiles to make sure the video displays correctly. I guess the Control Panel Video Colour "Dynamic Range" setting you mentioned should only affect video though, I'm thinking more of the "Desktop Color Settings". With the way my ATI is connected to my monitor (DVI) I only get a Dynamic Range setting under Video Colour anyway, but I think with other types of connection/TV some additional options appear that could affect non-video stuff.