No you don't want one of those all in one systems. They tend to be crap.
Depends what you want to do...if you're mixing house music like me then you want some pioneer CDJs (1000s are still the best but if you can't afford them then 200s will do the job, even if they are basic) and a pioneer DJM 800 or 700 mixer.
If you're into RnB or other stuff you want to scratch then you can get a program like Traktor and do it via a laptop. That means you can keep all your music on that rather than on CDs or vinyls. But honestly, CDs are still the easiest to use.