Well, like most things, the answer is ............ it depends.
Sucking is a very natural and calming thing for a baby to do.
I have given each and every one of my 5 kids a pacifier.
None of them are delayed in their teeth coming in, have any speech problems, or had any thumb sucking problems due to using a pacifier.
There are some obvious things you should be concerned with.
If you use a clip and a cord to keep the pacifier attached to your child's clothes make sure the cord is short enough that can't choke the baby.
Once your child gets to kindergarten make sure that they only use the pacifier at home. Being known as the only kid that had a pacifier in kindergarten could seriously damage your child's chances at getting asked to junior prom.
Seriously though, allowing your child to have a pacifier for the first few years of life is, in my opinion, not a problem.