First one can make a good photo even with a phone, making a great photo is a matter of composition another camera makes you not a better photographer. However another camera can give you some more convenience to use and raise the quality of your images.
The basics of SLR technology hasn't changed much in 60 years.. until 2008 that is with the release of micro 4/3 format.
I will not say that those are not good camera's but they are certainly not better than APSC format cameras which are most DSLR's.
There are 3 sensor sizes in use in consumer DSLR's, to be:
1: 3/4 format
When using this format, a 50 mm lens works like a 100 mm lens compaired to 35 mm film, the factor is 2.
2: APSC format, Nikon calls it DX, the Nikon sensor is a little bigger.
THe factor for APSC format is 1.6, thus when using a 50 mm lens it becomes an 80 mm lens compaired to 35 mm film, for DX the factor is 1.5 thus when using a 50 mm lens it becomes a 75 mm lens compaired to 35 mm film.
3: Full frame format, this are the most expensive camera's I consider them semi pro e.g. Nikon D700 / Canon 5D, and pro (not consumer any more) like Nikon 3D(x) and Canon ID. The factor for full frame is 1 when using a 50 mm lens it stays a 50 mm lens thus this camera works like 35 mm film SLR.
Whats in sensor size?
The bigger the sensor the bigger the whole camera will be, compacts have very small sensors and full frames the largest (35 mm) sensor of all. The 3/4 has the advantage of being a very small DSLR, the APSC is between the 3/4 and the fullframe regarding size and the fullframe is the biggest camera.
Why to tow a big full frame with you if there are small 3/4 size?
Well the bigger the sensor the less noise you have on the image. Bigger sensors result in sharper images. So pro's often use full frame, and sometimes they use even bigger sensors (Hasselblad 60 mm, very expensive).
In my opinion its not a good idea to start out with a 3/4 sensor format or with a fullframe format camera, I think a Nikon or Canon with the APSC format is a good choise, its affordable, bit bigger sensor than the 3/4th so theoretically less noice than 3/4th but don't buy the Nikon 3000 that thing seems to suck with noise, for the other Nikons you can't go wrong. Regarding lenses I see vickylover writing about a expensive 500 mm lens. IMO not needed to start too, keep it simple. Buy, beside the 18 - 55 mm zoom (best is to choose for the standard lens VR for Nikon and IS for Canon which means image stabilisation/vibration reduction) these camera's come with, a good 50 mm f1.8 or 50 mm f1.4 lens, these are affordable, and work like a 80 mm portrait lens on your APSC camera, and you have also some wide in the standard lens. You have to walk backward and forward to make photo's cause a 50 mm lens is a prime, but you save out a lot money a light sensitive zoom is soon 1500 US$. (You can always decide buy that expensive light sensitive 24-70 mm zoom later). All camera's are good today but I have to agree with Vickylover, buy a leading brand, the best buy is IMO a Nikon or a Canon these brands have a very very long tradition in building camera's and can build the best and there is a ton information and lenses available about these, and the lenses are more affordable than the 3/4th sensor format lenses.
As far I know from past Stacy always adviced to start out with a Rebel XTi not a bad choice, today this is the Canon 550D a great camera with very little noise (also 450D/500D are available for lower price). IMO get a 50 mm prime on it those are light sensitive, and right for indoor use with daylight and one has a nice set.
On the other hand in my opinion the Nikon gear is great too, I own a D90, and its a fine easy to use camera with a lot nice features as Active Daylighting (correct highlights automatically).
Bottom end if Stacy puts her today opinion again would be nice, maybe she did find out something new...
Mytime & Helen & Carmen