Active, passive, who cares? At the amateur or prosumer level it's just hobbiest bar room debates. Great mixes and productions are madeevery day on both passives and actives, as are lousy mixes and prodcutions.
Once one builds a real control room or mastering suite that is more than just the half-assed home project studio that 99.9% of us on this board have (including myself), and once one has 4 digits or more in their budget for the monitoring chain alone, then one can start talking about matching great amplification with great passive loudspeakers for a combo monitoring system that'll blow away active monitors that come in at half the cost or less.
But if you're talking near field monitors at $1000/pair or less in a quasi-treated bedroom converted into a home project studio, it doesn't matter enough either way to even worry about it. Audiophiles might hear differences, but not enough to make a difference in the engineer's ability to translate their mixes to the real world.
Probably one out of every five professional mixes you've heard on the radio in the past 25 years have been at least partially (and some entirely) mixed on Yamaha NS10 passive nearfields which, regardless of the quality of amplifier they may have been wired to, sound like absolute horseshit to the trained ear. But it became a standrd in control rooms all over the world nevertheless, because engineers learned how to work with them.
Get yourself the best sounding monitors you can afford and start mixing. Once youre ears and skills are up to the task in a couple of years and are ready for something better, then you'll know where to go and what to get instinctively.
G.