Adobe Photoshop is a must have for anyone calling himself a graphic artist. However, Photoshop is NOT a logo design tool. All logos should have their first, base version made within a vector drawing program (and have a basic one ink/one vinyl color version). You're shooting yourself in the foot if you go backwards in a bitmap program like Photoshop.
There are certain aspects of Photoshop that can be used for designing vector graphics. Photoshop's pen tool is excellent for creating clipping paths to knock out backgrounds from photographic objects. It can also be used to manually digitize vector paths from certain scanned objects.
One paradoxical thing: the keyboard shortcuts for Photoshop's pen tool are actually far better implemented than the shortcuts for the same tool in Illustrator or Freehand. And they absolutely blow Corel into the weeds. On the downside, Photoshop doesn't have all the technical vector editing tools those drawing programs boast. So you can't really do complete vector drawings within Photoshop. Especially any that have a technical or geometrical feel to them.