I learned photography in the early 1970's on a 35mm Miranda Sensorex SLR.  Lost interest in the hobby for a long time, then got back into it in 2009.  Wow, have things changed!  I have been using a Panasonic LX3 since December 2009 with very good results (fast Leica glass on the LX3) and was ready to get back into an interchangeable lens camera.  After doing a lot of hands on research, I decided on the D3100.I've had mine for two weeks now and for the most part, I am impressed.  The D3100 takes excellent images on automatic with the kit lens.  Composition is much easier with a proper viewfinder and the larger sensor makes obtaining shallow depth of field simple.  My semi-pro photographer friends have all commented that my images with the D3100 are more creative, more artistic and much better than with the LX3.Personally, I can see the enhanced creativity in my D3100 images but I feel there is little difference in image quality between the two cameras.  A bit of a disappointment on that regard (I was hoping for sharper images)  but others who have viewed my images disagree with me, so maybe I am being overly critical.  One thing I have discovered is the D3100's abilities far exceed mine when I take it off automatic - in other words, there is a steep learning curve going manual on this camera.  I have a lot to learn about exposure so I feel that the D3100 will be a great tool to help me enhance my photographic skills.I am a bit disappointed in the build quality - the SD card door is flimsy and moves around a bit when closed, the lens creaks.  The all metal LX3 has much better build quality than the D3100.  To be fair, the D3100 has better build quality than the Canons I tested.The D3100 feels great in my hands and is very nice to use.  The ergonomics are perfect.  I tested the D5100 and the D90 as well as all the Canon Rebels.  Of all of them, the D3100 felt the best.I considered getting the D5100 for its better sensor and screen, but the actual real world price difference was $400  (D5100 was being sold above sticker, D3100 was sold to me with a $100 Nikon rebate and an additional 10% discount from the retailer) and that was a significant savings.The 230k screen is adequate, not great, but acceptable.Overall, I am pleased.  I am looking forward to learning how to get the most out of this camera and I definitely feel it will help me grow as a photographer.Update, 6/1/11:  After reading Bryan Peterson's "Understanding Exposure", I am now shooting on full manual controls with my D3100.  I set shutter speed, aperture, ISO and white balance for every shot.  I also purchased the superb Nikkor 35mm f1.8 prime lens and a Tamron 70-300 telephoto zoom lens.  With my newly acquired knowledge about setting exposure, the images I am taking with the D3100 are excellent.  Images taken with the prime lens are tack sharp, that lens is amazing.  The Tamron set to 70 mm also takes sharp images (images taken with the Tamron at 70 mm are sharper than the kit lens and the Tamron does not get soft until 300mm).  With just a little post processing (I am using the View NX software that came with the camera), I can get the images from the kit lens to look incredible.  I am extremely satisfied with this camera and I highly recommend it. 

Question: What is the best instruments to take a good image ?
Answer: The D3100