Adobe recently acknowledged a print-related bug affecting some users of Adobe Creative Suite 5 applications, especially Photoshop: When you click the Printer Settings button, nothing happens; the Printer dialog does not appear. The Adobe support article implies that the bug is restricted to Epson printers and occurs only if you have chosen "Printer Manages Color in Adobe Photoshop's Print dialog box" (which I believe is the default option). According to Apple, the symptom is most likely to appear if you have just changed printers via the Printer pop-up menu.
While the precise symptom will never affect the bulk of Mac users, the solution is worth knowing because it will solve a wider array of printer problems.
Assuming you are running Snow Leopard, Adobe offers two potential solutions.
First, make sure you are using the latest Epson printer drivers (if you regularly use Mac OS X's Software Update, you should already be okay here). Additionally, install Epson's Common Updater 7.0. This adds Mac OS X 10.6 support to the currently installed Mac driver, but (if I understand the convoluted logic on Epson's website) is only needed for some of its printers, such as the Epson Stylus Pro 3800 and 3880.
If the software is already updated or updating has no effect, the second solution is to remove the printer from the list in the Print & Fax System Preferences pane. Next, Adobe says to go to /Library/Printers and delete the entire EPSON folder. Now reinstall the printer driver software (and Common Updater if needed) followed by re-adding the printer in Print & if needed) followed by re-adding the printer in Print & Fax.
Personally, I would first test the effect of just deleting and re-adding the printer in Print & Fax, before bothering with the more arduous task of deleting and re-installing the driver software. It appears that, especially after updating driver software, you may occasionally need to delete and re-add a printer to get the Mac to correctly work with the driver software. For example, I had a problem with a "communications error" popping up when trying to print to my Canon inkjet printer. Deleting and re-adding the printer in Print & Fax eliminated the symptom.