Dreadlocks/dredlocks is a term that might be popular, as is evidenced by the posts here, and is definitely not
offensive, as is also evidenced, but how you
use it may be. When I had them, I chose to call them "locks," and this is why:
That word is a Rastafarian word. It has connotations that a lot of white people may be oblivious to, but they're still there. I highly recommend reading
this (
http://www.knottyboy.com/learn/dread_history) before choosing your terminology. (The reason I like this site is they have multiple histories written by different people, so you can see the overlapping layers of meaning to the term. You can also find that on the Shittypedia article, but anyone who links there loses credibility so hey, you didn't hear that from me hehe.)
I don't think it's necessarily wrong either way, since the current generation(s) have co-opted the word to mean
any hair that is intentionally backcombed and matted into a collection of strands, so you're only communicating to your audience. But it's also
not their word, and the hip white kid meaning is only a tiny slice of what the rest of the entire planet sees when you say that word.
I disagree with Kytty (and a lot of other people, I guess) about wearing someone's religion as a fashion statement, but I think it's super-fucking-important that you know it's a fashion statement and that you're educated about connotations before you make a move like that. Fashion statements can be art, and art is communication. Someone might be offended no matter what you do--so just make sure you can defend yourself if they are, and maybe you'll even change their mind.
So to conclude my longwinded blathering, using a term that originated in a specific culture and religion for something that has nothing to do with that culture/religion should be done with your eyes open.