I will admit, when you're first learning 4th edition, it feels like there's not a lot of room for roleplaying. I felt that way when we started learning it (and teaching people it). I really do like 4th edition, though, and roleplaying is something you do between the combat encounters. It's as simple as having an idea of what your character would do, or speaking in a gruff voice for your fighter, stuff like that. It's a lot more fun when you have people to interact with, like the DM or the other players, but even one person doing it at the table is infectious.
My group made fun of my character for hoarding items when I first started with them. They were a lot higher level, and asked "What are you doing? They're just masterwork swords and armor- you already have better stuff!" but I just kept hoarding it anyway. With a bag of holding, it didn't matter. When it finally came around to a human town, I was able to sell everything and make a huge profit (with the GMs blessing, of course), and everyone was shocked.
My buddy Levi decided to play a goblin character with a thick Japanese accent, so he was speaking in character an entire game. It wasn't until like night one in the dungeon that he said "I'm going to go poop in the corner," and we all stared at him, open-mouthed. He looked around at all of us, staring at him and shouted "DON'T ROOK AT ME!" and everyone cracked up, laughing. It was just so unexpected.
Games are fun. Roleplaying just makes for great stories.
-kv