Many of us spend a lot of time looking for data to use for maps and I wanted to mention Natural Earth, a site whose tag line "Free vector and raster map data at 1:10m, 1:50m, and 1:110m scales" pretty much says it all. There's a lot of stuff here, and it's good for many purposes, and it's truly free, as in Public Domain.
The data can be dragged and dropped directly into Cartographica for use in your own projects, without any licensing issues, which is fantastic.Further, there are both raster and vector data sets, so if you need high-quality raster reliefs for the backdrop of a map, these may well fit the bill.
Raster files are in TIFF format (which Cartographica reads very happily), with all of the necessary files for Cartographica to recognize the coordinate system and display it correctly.
Vector files are in shapefile format, with the required .prj files so that they will be positioned correctly as well.
The maps are well done, the layers are coordinated for use with each other (vector and raster layers will match up, as will the vector layers with each other), and the Vector layers contain a variety of useful data built in, not just for setting attributes, but also for performing basic analysis.
There are some caveats, though. These maps are made mostly for use in Cartography, and they're in WGS-84 Latitude/Longitude, which makes them less useful for any kind of area calculation. The maps are also relatively low resolution (scales down to 1:10,000,000), which means that you're likely not to want to use them for maps at a very local level.
With that said, it's a great source of useful data, and their site contains good details on how the maps were created, and how you can get involved. Go visit today!