DSLR buying advise - March 2008

• The alpha 700 has live preview, which means you can see in the LCD while taking a photo, Nikon D300 has this feature too. But the downside is that If you hold a camera at arm length (so you can see the LCD), then there is more camera shake than holding the camera close to your body or eye. If you can flip the LCD, then you can hold the camera close to your body and avoid shake.
  
• Today's DSLRs use APS-C sized sensors which are smaller than the 35mm negative, this results in a multiplication factor for the focal length, so a regular 35mm lens becomes a 52mm on a DSLR which makes wide angle expensive. Canon started making full-frame sensor (same size as 35mm negative) cameras (ex- Canon 5D $2000) a couple of years ago and Nikon finally gave in (they insisted APS-C was good enough earlier) and released its own (Nikon D3) this year. This is the most significant change coming to DSLRs and may mean that APS-C DSLRs will be obsolete in a few years and replaced by competitively priced full-frame sensor cameras. That's worth waiting and paying more for.
  
• D40 is Nikon's entry level DSLR($500). D80 is a fine camera ($800). D300 is really good ($1700) and D3 is full-frame ($5000). They seem to have even introduced a D60 now. D40, D60, D80 use SD or secure-digital which are thin memory cards. D3 and D300 use compact-flash which is bigger and more robust. Incidentally the D80 replaced the D70 I have, but the D70 uses compact flash. That's a cost savings for Nikon hidden there. The Nikon D40 can take great images and seems well priced. A used D70 may be a good buy at $350- $450. 
  
• Canon, Sony have similar models and they must be equally good.
  
• Canon's image processing yields more dynamic range, Nikon's is more neutral. Personally, I like Canon for flowers and Nikon for people.
  
• Canon, Nikon, Sony/Minolta, Pentax, Olympus all make great cameras.
  
• Pay close attention to viewfinder magnification (about 0.9x or higher is good)
  
• Good lenses are important and expensive. If you don't like flash, make sure to get a bright lens (lower f number)
  
• DSLRs have much less noise than the tiny sensors in the point and shoots. They also have better depth-of-field control. Evaluate if you want a portable camera. If so, get a good point and shoot. You may take more pictures than with a DSLR. Given a price point, the heavier the point and shoot camera is, the better its built.