Hi Brian,
I do agree that logos (for the most part) need to be created in a vector graphics program such as Adobe Illustrator or Macromedia Freehand (if we go WAAAY back). The reason for this is all curves, lines, fills (except for gradients) are rendered with mathematical points of reference and can be scaled uniformly to any size without degradation to the image. This is different from Photoshop which is a Raster (bitmap) graphics program which uses pixels for reference. Pixels are 1 size and when scaled, the pixels will be stretched to fix the new size. This creates 'pixelation' and additional noise in the image.
To get a better idea of this concept, try this:
1. Make a copy of a photo you have to not overwrite the original.
2. Take the photo and resize (Image > Image Size) the image smaller (say 600px x 400 px).
3. Save the new image. Close it and reopen it.
4. Take the image and resize it larger, say to about 400% (2400px x 1600px)
5. At this point you should see that the image may be blurry, noisy, not sharp or any combination of these.
If this image was printed to size, the print would not look very good. This is an example of image degradation. This same effect occurs when raster (bitmap) graphics are resized again and again and again. The pixels bleed together and stretch to complete the new size. The image has no idea it's being distorted. This whole concept is different in a vector graphics program like Illustrator.
Image resolution (72, 150, 200, 300ppi) has a lot to do with the amount of degradation to an image. 72ppi is used for screen *at size. This mean web graphics, tv graphics, etc. 150-300ppi is used for small to large caliber print jobs and can be scaled minimally without much degradation to the image.
If you decide to create a logo in Photoshop, make sure you create one larger than what you'll need. It's always better to scale down than scale up. I recommend making it 300ppi resolution and (depending on purpose) at least 3000 pixels wide.
If you can, learn Illustrator and utilize the power of vector graphics. It's got a steeper learning curve than Photoshop, but it's a powerful program.
I hope I helped you out. Good luck.
