Help with zooming

Hi, i recently picked up a copy of Photoshop CS4 extended from my friend, and im a little new. The reason i got this was for my Intuos4 which will be arriving tomorrow. In the mean time i though i could practice a little. Ive been checking out videos of people drawing and coloring already existing images, so when i tried to follow along with this tutorial
http://tutorialchamp.com/index.php/beginners-guide-to-digital-coloring/
I noticed he was zooming in a lot, and the problem is when i go to zoom in, the lines obviously become distorted and lose a lot of quality.
Now i know its not my pc because im running 1.5 gigs of ram, a xfx geforce 8600gts , and an athlon amd 64. Ive also enabled OPENGL and updated my video drivers to the latest version.

My main question is, why cant i zoom in and out like the videos and not lose a crap load of quality.

Another reference is this video
http://www.youtube.com/watch?v=FcYASZMxqnI&feature=related
, hes clearly zooming in and out and not losing any quality when doing so.

Thanks to anyone who took the time to read this and help me out...im stumped on this and cant find an answer.

Hello there,

This might no be the issue you are having, but I know that at odd zoom percentages the image is low quality, like at 30% or maybe 60% the image looks like crap, but at 25, 50 or 75% it looks fine,

thanks for the help, your right though it does look better at a multiplication of 2. As a total newb ive been slowly learning and i think by setting the page at a higher resolution, i can zoom in really far without seeing any pixelation and loss in quality, i guess its just the picture i was testing had a low resolution dpi, and was loading at a 100% zoom right off the bat, but my other pictures with a higher dpi i can zoom into really close without pixelation.

Thank you for your help though, your suggestion made me realize my problem :D