My recently-pregnant-for-the-first-time friend has asked me what she needs to buy and it occurs to me that it's very personal.
And, as with all very personal things, it's probably best to ask MN about it 
I really loved my ring sling, eventually, but when I bought it, I thought it was a vast waste of money as I couldn't work out how to get DS2 into it - once he sat up it was much easier. But my wrap sling, I didn't use nearly as much.
I can't really remember much else - bit of a sleep-deprived haze. I seem to recall numerous muslins, but they were v useful...for me, though not everyone will use them, I guess! 