i echo the other posts ....SOFTWARE is the main influence for buying hardware.

TRAKTOR - NI hardware
SERATO - RANE/Vestax
VDJ - anything clockwork and made from bellybutton fluff


then onto MUSIC style .... are you 2 or 4 deck, pre or post effects.

You need to think more before jumping in, it's a BIG decision and can easily cost a lot of money when you change your mind.

I have several complete systems now, and settled on the S4 for EDM, and AUDIO8DJ plus TT's for house, soul, funk, R&B (not rnb).

If you are playing in clubs, maybe an Audio4 / Audio6 (two decks) or Audio 8 / Audio 10 (four decks) would be the right solution. Timecode is easy to use, ultimately satisfying (turn off sync and beatmatch oldschool) and very portable.