I'm sure it's come up already in the thread how well 4e makes characters feel heroic in play, but here's a timely example from just a little earlier this evening.
I'm playing in a 4e game, with a 12th-level dragonborn paladin. A bunch of enemies are clustered in a convenient 5-by-5 area, so I waltz up, unleash dragon breath (minor action, close blast 5), shout of condemnation (standard action, close blast 5, one of the effects is it marks enemies via the divine sanction mechanic), and then spend an action point for just radiance (standard action, close burst 5, targets everyone marked by me).
Just a little later in the round, the BBEG (Skalmad the troll king) unleashes an encounter power that deals a crapton of damage, and because an ally within 5 squares of me is attacked - in fact, the power was going to nail 5 of us! - I can use an immediate interrupt to use strike me instead, causing the attack to miss all my allies and hit me automatically.
I painted a huge target on my back - and we had to call it a night at the end of a round, with something like three enemies acting before the party cleric does, so I could be going down - but that felt amazing to pull off!