Good question. While this isn't something I'm personally dying to know, from everything I've heard this is something that's going to ROCK in 4th Edition. From what we know:WayneLigon said:Classes and multiclassing, which also covers how spellcasting will work.
I'm also most interested in alignment: how extensive is it, what do the various catagories mean now, etc.
This got a least sort of an answer already. It was said that magic items will still be things your characters want and will still be a benefit and part of your character, they just won't be mandatory anymore.Wulf Ratbane said:Reduced Dependency on Magic Items
1) Will there still be magic items that give bonuses to game mechanics?
2) Will adventurers still find gold and other loot?
3) If (1) and (2) are both true, then by what in-game rationale do you keep players from trying to spend their loot on magic items to improve their characters?

(Dungeons & Dragons)
Rulebook featuring "high magic" options, including a host of new spells.