Here's how I would envision the difference between a say 1st level vs 10th level character. Replace "Energy Points" with "Encounter power" to suit:
Fighter 1
HP: 15(Con)
AC: 15
Attack: +5 vs AC, 1d8+5 damage.
Power Attack (class feature): 1/enc, +1d8 damage on a hit
Takedown Attack (feat)...