Landscapes, macro, portraits, indoor, wildlife, sports

I had the P500 since December, 2011 and, as an amateur like you with all the same interests you mentioned, I am quite satisfied with it especially on long or zoom shots like my birdwatching which I do often (maybe not so clear but good enough for me). Friends who are owners of DSLRs like the D5100 envy my zoom shots because they are stocked on their kit lens due to high price of telephoto lens. With its improved IQ and stabilization, I recommend the P510. In fact, am waiting for the price to go down and be buying it also. Thanks.

Always go DSLR if comparing with p&s . The DSLR will have a huge advantage in image quality against the P510 and you will have more control about what you want to shout and what way you will shoot . The D5100 will work as you like at every situation but P510 won't. Also the photographs of landscapes, portraits, close-ups with the D5100 will be a class apart then similar photos taken with P510. As far as zoom is concerned you can easily crop the picture on your PC and then keep it but it will still be of good quality . Since the sensors are totally different, a cropped pic taken with a DSLR will be better than the full zoomed pic of a p&s .I have D5100 and I do this with a 18-105 mm . Also while you photograph your favourite things, photography will become a hobby, a recreation .

Soon you will have needs of a DSLR . And the Nikon D5100 is an excellent DSLR with wonderful value for money . The D5100 is the number one DSLR on SnapSort's recommended list , beating other pro-level DSLRs . Here is the link - recommend at snapsort.com

Also, most importantly, with a DSLR , you will learn the art of photography .  

A deer from the distance without scare it? 200 mm zoom is not enough. I recommend Coolpix P510 - it is also smaller to care in the woods and one lens will cover all your needs.

p510 is great for amateur needs  however comparing p&s and a dslr is not recommended as the sensors are totally different -  cropped pics from a  dslr could beat full zoomed pic on p&s  - the ease of the p510 makes it a complete amateur package -  dslr is a complete next stage if you wish to move on and drag some gear along for different situations -

You'll really appreciate what this camera has to offer for what it is.  You said you'd remain in the amateur category, therefore, you'll be better off with this camera.  The P510 (which I also own) is amazing for a "point and shoot" yet it's more than that.  You'll feel like a professional with the photos you'll take!  Good Shootin'

D5100 (or any other decent DSLR) can keep up with u while your photography mature. Only u need to get a new lens.

on the other hand P510 will not be able to cope up with ur maturity.

The zoom on the P510 is much better suited for bird and wildlife photography.  The lens you mentioned (55-200) would only be about a 3.5x zoom and so would not give you the range you are looking for.  A DSLR is better for highspeed photography (not as much blur) but I find the P510 much easier to carry than lugging around an SLR with a bunch of lenses.

But take a look in the Nikon 70-300 lens for birding! You will probably need the 100mm and better VR ...

If you still have the bird not big enough, crop the picture slightly on the computer, so you will be able to increase to theoretical ~500mm, the quality should still be able to stay relatively high, even for bigger prints!

Not going to even begin to compare these 2 camera's.

Apples and Oranges mate.