People are always asking me "Hey, what is that you're playing?" or "What is the best synthesizer for a beginner?" or "What's wrong with me?". It can be difficult, if you're new to the medium, to know what is the best instrument for you and with so many makes and models out there where does one even begin? I'm no expert on the subject, but I have been going through my own trial and error process with analog synthesizers since the mid 90's and this is what I've learned:
It's all about control. There is no point in buying a synthesizer (if you're just starting out) that is completely cut off from the rest of the world. You're going to acquire other little machines and you're going to want them to be able to communicate with one another because that's how pleasant, listenable, electronic music is made. If you want to be remarkably old fashion you'll need to make sure your synthesizer has CV & Gate inputs and outputs and if you want to be a little more modern (and, dare I say, have a lot less fun) make sure it has MIDI.
Of course there are many other factors: voltage controlled or digital oscillators, how many oscillators, monophonic or polyphonic, modular or fixed. These are all decisions only you can make, and the best way to go about it is to educate yourself. But the one bit advice I will give you is, and it is the same thing I will tell my children, my grandchildren and my great grant children: when it comes to electronic music.... make sure you're always in control!