Good Video card and monitor to go with-Radeon vs.GeForce

I am undecided against getting one of the faster Radeon cards vs. the
GeForce cards. I don't do a lot of gaming but do a lot of video work
making DVD's, etc. What is better to go with?

As well, I want to get a LCD screen in the range of 17-19 inches. Are
the widescreen good? I can imagine they are mostly for watching dvd's
on the computer or are they good for general computer work?