I currently use Photoshop 7 for Windows and Photoshop 7 for my mac, as well. Most of what I use them for are web designs - i.e. the logo for DaniWeb, some designs for other websites, etc. I've actually never tried CS so I can't compare myself. So now my question: Is it worth it for me to upgrade to CS?

The only thing that has affected me is the save / open new hot keys, now it is ctrl shift s to save as and now pressing alt, then f, then s goes to open as.

Here is a list of new features though.

// Description
 	Get superior results faster with Adobe® Photoshop® CS software, the powerful new 	upgrade from Photoshop 7.0, and take advantage of indispensable new features for 	graphic and Web design, photography, and video.
 
 	New Features Include:
 	* [Improved File Browser]: Quickly preview, tag, and sort images; search and edit metadata and keywords; and automatically share batches of files from the improved File Browser.
 	* [Match Color Command]: Achieve a consistent look between package shots, fashion photos, and more by instantly matching the color scheme of one image to another.
 	* [Histogram Palette]: Monitor changes to your image in the Histogram palette, which dynamically updates as you make adjustments.
 	* [Shadow/Highlight Correction]: Quickly improve the contrast of over- or underexposed areas of an image while preserving the overall balance of the photo using Shadow/Highlight correction.
 	* [Text on a Path]: Create eye-catching typography by placing text on paths or within shapes. Edit the text at any time, even in Adobe Illustrator® software.
 	* [Integrated Digital Camera Raw File Support]: Get truer, higher quality output by working with the complete raw data files from most major digital camera models.
 	* [Comprehensive 16-bit Support]: Perform more precise editing and retouching with expanded support for 16-bit images in core features, including layers, brushes, text, shapes, and more.
 	* [Layer Comps]: Create design variations for clients more efficiently by saving different combinations of layers within the same file as Layer Comps.
 	* [Macromedia Flash File Export]: Use ImageReady CS to create Macromedia® Flash™ (SWF) animations, complete with vector artwork and variable text.
 	* [Customizable Keyboard Shortcuts]: Customize, save, and print a summary of your ideal set of keyboard shortcuts, so the functions you use most are always at your fingertips.

If you ask me, it's worth the upgrade for Layer Comps alone.
This is a great way to have multiple versions of a file for client approval.

I agree with Kezz the upgrade is worth it, but if you dont work heavily with images and Photoshop 7 serves you right, then you may want to spend you money in something that you might use to improve the quality of the image you start with. A scanner upgrade or a new Digital Camera.