(long post so apologies before you start to read)
There's a few things you need to ask yourself. Are you going to try to be a working DJ? How much money do you have to play with? What style are you going to mix? ( I assume dark wave/industrial etc)
I started DJing in the 80's on turntables in clubs using vinyl and beat mixing was the only way to go about club DJing. I bought many Turntables as they became better engineered and better technology was used to build them.
Last year I sold all my vinyl ( around 5000 12'' singles and maybe 1000 albums ) and after the tears (vinyl junkies will understand) I bought control discs for my turntables and a piece of hardware which allowed me to mix digital music with a live vinyl feel. (Torq and connectiv respectively)
Finally, early this year I bought a midi controller (Xponent) and I run it straight into the laptop to mix the same digital music.
Depending on which DJ's I speak to, some say learning on turntables and experiencing the tactile feel and the lag and all sorts of things that turntables and vinyl offer ( jumps, scratched after much useage, background grinding sound, needle quality) they were much better digital DJ's when they swapped to digital rigs.
Others have never seen a turntable or vinyl let alone used them and have no problem using a midi digital rig.
In the end is a personal choice thing. Midi DJing can make life very easy as there are auto sync buttons and various other tools that can make it so very easy to beat mix.
The cost of equipment is an issue. If you are, or intend to be a working DJ then the cost, in the end, will cover itself with the payoff from gigs.
If you are going to be bedroom DJ then you really dont need tom spend large amounts of money.
Starting with a cheaper DJ rig then upgrading can cost you more then just buying the mid to top line DJ rigs.
Look at the DJ's you like and see what they use, see how they go about their craft.
Ultimately, it's not what you use to mix, it's how you use the gear. How you blend styles and beats and whether you choose to learn to beat mix without using the easy sync buttons and so forth. If you decide not to learn to beat mix then you would be just as smart to find a little cheap DJ program and play one song after another without worrying about blending beats.
With my rig I mix house, techno, funk, aggrotech, industrial, darkwave, hellecktro and never had a problem with the rig or the software. Do your research and look at the options with the equipment you are considering buying.