Much depends on whether you just wish to do this as a hobby or perhaps use this equipment later to become professional. As already stated, the Technics deck SL1210 is the preferred choice of the professional but it ain't cheap. If you wish to go pro and maybe use the same equipment that you start with, go for direct drive turntables and not belt drive. Belt drive take some time to get up to the correct speed compared with direct drive which are almost instant start. and will make any mixing you do alot easier, you will have to get used to direct drive if you eventually end up in a club using their stuff so it's best to start off on the right foot.
To answer your original question, the Numark DJ in a box is good value if you just want to be a bedroom DJ and have a bit of fun . It will not survive for very long on the road doing gigs and you would be better to save a little more cash and go for better equipment. I personally no longer use vinyl. I am a mobile DJ who uses CD's, although the computer and MP3's idea is becoming more attractive to me at the moment.