Fl Studio is a all-in-one DAW that has a strong appeal for sample based beat makers and composed style beat makers. FL Studio was formerly called Fruity Loops but because of the negative connotation of the term "fruity" it was renamed.
FL studio has been used in commercial recordings from artist such as Jay-Z, Destiny's Child and Mary J. Blige. FL Studio has a very strong following on the rap and techno genres.
The current version as of this writing is version 8.
The Good
FL Studio is extremely powerful. Creatively FL Studio can deliver just about anything you can think up. It has a very strong support for sample manipulation. This is one reason why sample based beat makers are find it so useful. I would say it has the best sample editing capabilities (recording, chopping, slicing, tuning, etc..) of any DAW on the market. Truth is it blows hardware like the AKAI MPC out of the water when it comes to manipulating samples.
FL is relatively easy to use from the start as it starts you off in a sample based pattern editor. Point and click beat making at it's finest.
FL Studio audio processing is among the best out there and has shown consistent top marks in comparison testing.
MIDI support is also included.
The relatively low price ($199) and the lifetime updates are two very strong reasons why newbies to the beat making game go for it. When I originally purchased it it was $99 and I have had updates ever since. Many new features are added with each release and new major releases tend to come out about once a year.
FL Studio has the ability to use VSTs for both effects and instruments which makes getting new sounds from it, easy and affordable. The sheer amount of free VSTs out there make it especially appealing to the beat maker on a budget.
The Bad
FL Studio has a bad rap because of the stock sounds that come with it. They are not as polished as something like Reason and there is some confusion as to how to load the various sounds from the library. This can be easily overcome however because of the number of free and commercial plug-ins and drum kits that FL can use.
Most notably for the beatmaker is the absence of top notch drum kits. Again, this can be corrected by supplementing the library with other sources.
Some advanced functions can be difficult to use. There are advanced things like automation controllers that can be driven by mathmatical functions. Don't be scared by this however. I like to think of it as more bang that I can use if I need it, but is not neccesarry. There are many video tutorials on the FL Studio site that can help and one of my favorite FL Studio tutorial sites, Warbeats.Com is another excellent resource.
The Ugly
Some people say the interface is a sore spot for the program and it can be. Many of the controls are tiny when viewed on high resolution displays. This can be a source of frustration when trying to dial in that knob to just the right place.
FL has a primarily dark color theme which some people find not as easy to view for long periods of time when compared to light based themes.
Conclusion
Whether you are a sample based beat maker or prefer to compose your own beats from scratch, FL has all the toold you will need. Be sure to get familiar with plugin sites like KVRAudio.com and tutorial sites like Warbeats for maximum enjoyment. The lifetime updates insures that 10 years from now you will still be on the latest and greatest.