There are a wealth of crop frame cameras on the market these days, and many of the bodies have as many features as full frame cameras, but with a much smaller price tag. Full frame cameras still have their advantages, though.
The term "full frame" means that the digital sensor in the camera is the same size as an old strip of 35mm film. This means that you don't have to do any clever calculations with your lenses -- whatever the stated focal length is, that's what you get! File sizes and megapixel counts tend to be higher on full frame DSLRs, and the cameras come with a host of features. Full frame cameras also tend to have fewer problems with various artifacts, as lenses don't have to cope with the crop factor. If you're serious about photography, and if you're thinking about making a career from it, these are the cameras to consider.
Here are the best full frame cameras on the market at present.
1. Canon EOS 5D Mark II
I'll freely admit that this is the camera I use, as I've been a dedicated Canon user for quite some time! This isn't Canon's top of the range camera (that's the EOS 1DS Mark III), but it has more than enough features to keep most photographers happy. The Canon EOS 5D Mark II is lightweight and compact, yet it has 21.1MP of resolution and full HD video mode. It is widely regarded as one of the best cameras on the market for shooting films, and its image quality is amazing. The 5D Mark II also is considerably cheaper and lighter than the 1DS!
2. Canon EOS 5D
If you don't have the budget for a 5D Mark II, then you can still pick up its predecessor -- the EOS 5D -- for a much lower price. If you do a bit of research, you'll also find a lot of people selling them secondhand (usually because they've replaced them with a Mark II). Granted, the original 5D only has 12MP of resolution, but the image quality is superb and color rendition is lovely. The camera also produces stunning results, even at high ISOs.
3. Nikon D700
A little disappointingly, Nikon has shied away from very high megapixel counts in some of its FX cameras. The D700 only has 12MP, and, to receive a higher resolution, you'll need to invest in Nikon's flagship camera, the D3X (which has a resolution of 24.1MP and costs more than $6,000). But, in all other respects, the D700 is a fantastic camera. It's ruggedly built and has a fast frame per second rate of 5fps. Even though it has a slightly lower megapixel count, it will still outperform many of its crop frame rivals.
4. Sony A900
Sony is a relative newcomer to the full frame market, but the Sony A900 camera offers a lot of features for a very reasonable price tag. It comes with 24.6MP of resolution, HD movie mode, and a capability of 5fps. All Sony DSLRs come with a clever feature called "Steady Shot Inside," which means that image stabilization goes on within the camera body. This means that Sony is able to keep the price of its lenses lower than its competitors, which put IS into their lenses.
5. Hasselblad H4D-31
Here's a suggestion for a full frame camera if you win the lottery -- the Hasselblad H4D-31. Hasselblad was the undisputed king of film photography, and its cameras were even taken to the moon! The H4D-31 is its entry-level digital camera with a whopping 31MP of resolution. (Hasselblad does have cameras that go up to 60MP!) Because Hasselblad technology is based on medium format cameras, the sensors are much larger than in normal DSLR cameras, and the image quality is quite simply amazing. However, you'll need around $13,000 to buy one of these!