Remember a few weeks ago, I mentioned how if you want to be extra-cautious about preparing for Wrath of the Lich King, you should figure out a calm, easy way to farm gold that won't burn you out? After having hit the current level cap on the beta realms... I still recommend that, if you want to be extra prepared. If you're a very casual, don't worry about it too much, really. It's not that big of a deal. Leveling will get you enough for the bare necessities. If you're the type that wants to start leveling professions and gearing up immediately upon hitting the level cap though, think about going into Wrath with at least a couple thousand in your pocket, which really isn't that hard of a task.
Moving past that, though, a lot of people have asked about gear across all classes, but mostly Hybrids. Hybrids have asked because all of the Healing classes are amongst them, and if you're a Healer you may not necessarily have a set of DPS gear. My first comment on this: Don't worry. Really.