I agree with PP about the sling. That is the first carrier I had and I think that was a good starting point. I have since gotten a ring sling, wrap and mei tai. I haven't used the mei tai yet (just got it the other day). I love my wrap most right now because DD squirms too much in the slings at times. So, depending on what I am doing, the wrap might be best. I can't wait to try out my mei tai this weekend. I personally think that having a regular pouch sling first would make having a ring sling easier. A ring sling is easy enough to use, but I think having had a pouch sling first and knowing what the fit was supposed to be like made the ring sling easier for me when adjusting it. But that's just my take on it. The wrap isn't hard to use, there is just a bigger learning curve because of all the fabric and different tying choices.
As far as brand, I have a Hotslings pouch sling and I like it. They are pretty highly recommended. The ring slings I have are a Zolowear (highly recommended) and an Oopa (also highly recommended, gorgeous, but a bit pricey). The wrap I have is a Didymos (again, highly recommended and a little more expensive than others). My mei tai carrier is a BabyHawk (again, highly recommended). All of my recommendations I got from ladies here on the ATB forum and they steered me in great directions. I love all the carriers that I have!!
That being said, I think you are going to get a good product with anything that you buy here at ATB. They sell all good quality stuff. As the PP said, a lot of it is personal preference on style, color, design, material, etc.
Best of luck. HTH!!!