Buying a DSLR is not like buying a compact and that is true 
You can buy a compact every now and then when a good model comes around but the same cannot be said of DSLRs.
You’ve got to think more carefully when buying a DSLR because you can’t go on buying a DSLR each time a “better” model comes into the market.
Firstly, DSLRs are expensive and can set you back ranging from a few hundreds to a few thousands if you count the investment you need to make to buy the flash gun, battery grip, tripod and purpose-built lenses. You need all these, by the way, to fully exploit the potential of a DSLR.
Secondly, buying a DSLR is almost equal to buying into a system, meaning the deeper you are in a system, the harder it would be to switch to another, unless you have a large budget to finance the switch.
By the way, Digital Photography Review has updated its “Buying A Digital SLR: A Beginner’s Guide” article, so you might want to check that out before buying yourself one.
The article discusses issues like why you need a DSLR, a brief explanation on what a DSLR is, sensor size, anti-shake systems, speed, size, weight and durability, screens and live view, ease of use, advanced photography features, movie modes, the possibility of becoming an “addict” to a system, and the advent of mirrorless interchangeable lens camera.
Here is the article, “Buying A Digital SLR: A beginner’s Guide.”
