Excellent points made by Haly,

I have a Ranger thats lvl 34 and she currently dual wields. Now this is
a choice that I made which seemed to "fit" my toon and her personality.
I also have a Warrior who just uses a 2hs weapon. I plan on building up
his skills in the other areas too but a 2hs seems to "fit" him the best.
It's all about how you want to play YOUR toon, there is no right or
wrong way. One thing you may want to consider is that some weapons carry
some cool abilities. such as a damage bonus or spell. This may be
something you might want to keep in mind and also in some situations you
can benefit from these added bonuses. You asked a very good question, a
basic one and really IMHO is something that alot of players really don't
think about. They are more interested in getting the uber twink gear
which is nice but if you can't use it to it's full potential and to your
advantage, it's really not that uber.

Hope this helps!
Durgaa
Ranger of the 34th season. (And still learning everyday!)