I went with 160x230 for my DVD cover images. This allows for 8 DVD covers per page while still retaining the firm key labels at the bottom of each page as seen here.

Couple things to keep in mind when looking at the example pic...
The text via the text labels does not show as anti-aliased in the editor, only in the remote. In the remote text looks fantastic. Also, the background panel in the system area, system items, and firm key labels as pictured are not part of the original screenshot. I added them to the screenshot after the fact in Photoshop as to best represent the final result as seen in the remote.


There is no comparison to the look of the graphics in the Simulator versus the remote. In the Simulator the graphics look horrible due to the screen area of the Simulator only being 300x224 as seen on your computer. This results in graphic anamolies rendering the Simulator less than useful for reviewing your graphics work. The only way the Simulator can accurately represent what is seen in the remote (and that's only to a point) is if the screen area of the Simulator is a true 640x480 as seen on your computer monitor. At this size however, a 1600x1200 desktop needs to be used. Any desktop resolution lower than that and the Simulator would not fit on screen.

During the beta test I brought these things up and even provided a pic showing how large the Simulator would need to be to provide a true 640x480 screen area at a 1600x1200 desktop. As you can see in the pic this allows for ones graphics to be represented accurately in the Simulator. As for the large desktop resolution, only at a 1600x1200 desktop can you even fit 4 pages on the screen at 100% zoom while working with the editor. This is my preferred desktop resolution while working with PEP, so I'd be in favor of the Simulator being displayed at the size seen in my example pic. The other item of note regarding the Simulator. Unlike PPENG, the Simulator in PEP does not run as a separate process. This means that while the Simulator is running the editor can't be used. I find this an unwelcome change as there is no way to check over your work via the Simulator making changes/corrections along the way in the editor at the same time. Hopefully we'll see the Simulator running as a separate process at some point via a future editor update. I put the request in anyway, so it's certainly a possibility.