The worst part of multiple tank syndrome is that
you tend to overestimate how much you enjoy tank maintenance. Sure, you can enjoy dozens of new fish; setting up a new tank is interesting and fun, particularly if you've gone through a tough time with your first tank and you want another go at it to do it the "right" way.
{note, in rereading this it sounds rather harsh. I didn't direct these next comments at the original poster...just some thoughts about MTS after having gone through it myself

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However, 6 months down the road, are you really going to keep up with regular water changes on multiple tanks? Is it going to be as fun if a mystery disease that you can't seem to eradicate wipes out an entire tanks worth of inhabitants? Do you have enough money, space and time to accommodate a new tank? How much time and enjoyment are you getting out of your current tank? It's important to be honest with yourself about these facts. Would it be better to get a larger primary tank instead of multiple smaller tanks?
Fish are living things. An aquarium isn't like furniture-- you just can't return it (and all the living things inside it) when you're tired of how it looks or bored of the maintenance.
Would you buy multiple dogs or cats without thinking about all these things? HTH~