The choice of software is usually the second one to make, right after deciding what kind of DJ you are/want to be. Or more precise, what your (intended) workflow is gonna be.
BTW, is it the Mixtrack Pro? If not, it doesn’t have a a built-in sound card and you might end up having to buy one of those too. Which you, most likely, won’t use after an upgrade as anything above this level typically will have sound cards built-in.
For me Traktor would be far worse than anything else. Serato would work for me, but I switched (from Traktor) to Mixvibes Cross before I had a Serato-supported controller. Then again, for some other DJs Traktor is better than anything else.
It’s really impossible for someone else to tell you which to use. As a general observation, Traktor seems to work best with Native Instruments gear, but at this stage of your development as a DJ you’ll get away with using Traktor with an MT1 (assuming it’s supported by a good mapping). When you do upgrade in the future and want to stay with Traktor software (if that is what you decide to go with now), I’d suggest moving to Traktor/NI gear exclusively.
Final word. I don’t think the original MT was supported by Serato, so that won’t work. For Traktor I am not 100% sure, but there are quite some (older) mappings around, so you might get lucky. I am pretty sure it was designed for VDJ so that most likely will work well, but not sure what the cost is there. Mixvibes Cross (which I mentioned before) does support both the MT and the MT Pro natively. They have a free, time-limited (two weeks I believe) trial version with full features. After that it is only 49 bucks/euro for the full version.
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