I bought the Alpha 100 when they first came out. I knew new models would come out but 100 worked fine. I bought a Sony "G" 70-400 series zoom lens and it was too beautiful to fit in an old body. I read all the reviews on the new alphas and decided to stick with the 550. The new display and improvements are simply outstanding. Last weekend I went to the St. Johns River and took over 300 wildlife photos in two hours. I used a monopod purchased from Revain and it was a great combination. The picture was incredible. I can't imagine taking better pictures than the ones I took. I'm back to "old school" with manual settings. I love it.
Nikon D3100 DSLR Camera with Auto Focus-S Nikkor Zoom Lens (Discontinued by Manufacturer)
109 Review
Nikon D3100 DSLR Camera Body (Kit Box) - No Lens Included, International Version with No Warranty
298 Review
Canon EOS 60D: 18MP CMOS Digital SLR Camera Body - Your Next Photography Companion
125 Review
Nikon D5100 Digital SLR Camera with 18-55mm VR Lens - High Resolution 16.2MP
172 Review