See my blog post for further discussion of this image.
My June 2008 DSLR camera collage is by far my most popular image on Flickr. This is an updated version of that composite of publicity photos from various DSLR camera manufacturers, current as of the beginning of January 2009. Images are © 2006-2009 Nikon, Canon, Sony, Olympus, Panasonic, Leica, Pentax, Samsung, Fuji, and Sigma. Thanks also to DP Review and DC Resource for making the images easy to find.
Prices here range from around $450 (with lens) to $20,000+ (no lens). The smallest cameras in this bunch are the Leica M8.2, Panasonic G1, and Olympus E-420. The heaviest are the pro monsters, the Nikon D3/D3x, Canon 1D/1Ds Mark III, Sony A900 (with grip), and the upcoming Leica S2 medium format DSLR.
What's new since the last collage are DSLRs that take movies (Nikon D90, Canon 5D Mark II), new form factors at the low end (Panasonic G1 with interchangeable lenses but no mirror box) and high end (huge sensor and lenses on the Leica S2), and renewed emphasis on low-light performance. Sony's and Nikon's entry into the mega-megapixel race with the A900 and D3x are also interesting.
Relative camera sizes are not exact. The positions of the various models vaguely reflect my impressions of a combination of price, features, and market segment. That's quite subjective, so you could easily argue with my placement of some of them -- and sometimes I just had to bump things around to make them fit. Take the image as a general guideline. Look down the columns to see how different cameras from a single manufacturer compare from low-end to high-end; look across the rows to see roughly comparable cameras (in features, price, or both) from different makers that compete with one another.
Have fun in the comments. I'll probably update this again in another six months.