I wouldn't get a Moby-style wrap - it will get too stretched out once your kiddo is past baby stage. If you like wraps, looks for woven or German-style wraps, as the fabric will accomodate heavier weights for longer.
IMO, the ultimate carrier to have, once baby can hold their head up is a mei-tai. Join thebabywearer.com - http://thebabywearer.com/ (look for register on the top right) and then start reading to forums (same line as register, third from left ... don't mean to be overly descriptive, I've just heard so many folks say they can't find the forums when I send them there :)
You can read about the different types of carriers, and then, once you've narrowed it down, search the FSOT forum to find one in your price range.
I've been wearing my youngest (now 16 months) daily since she was born. As soon as she was ready for a back carry, my BabyHawk mei tai was great. But since she still takes two naps a day in the carrier, I wanted something with a structured waist - I ended up swapping for an Olives & Applesauce half-buckle carrier and have been in love with it since my first wearing.
The carrier has been a godsend while trying to deal with a preschooler and a toddler on my own!
You can do back carries with the woven wraps I mentioned earlier, as well, I've just never gotten the hang of it. Do check out the local babywearing meeting (I think I saw someone mention it in the previous replies) as you'll be able to try on different types of carriers and find what works best for you.
Good luck!