The basic math of 4e advancement:
Over 29 levels, from a starting level 1 character (with no magic items) to level 30: To-hit, AC, and Fort/Reflex/Will gain +21 from levels/enhancement bonuses.
Assume you split your stat boosts to two stats that add to different FRW defenses. One of these stats is your primary attack stat. If you wear light armor, one of these stats boosts AC.
AC gains +6 more: either +6 from Masterwork Heavy Armor, or +2 from MW Light Armor and +4 from increases to an ability score which adds to AC.
To-hit and your two strong FRWs gain +4 more from Primary/Secondary Attribute advancement
Your one weak FRW gains +1 from the ability score boosts at levels 11/21.
So AC gains +27, to-hit and your two strong FRWs gain +25, and your weak FRW gains +22.
Over these 29 levels, monsters gain +29 to their to-hit and to all defenses. Monster to-hit rises 2 faster than PC AC, 4 faster than a PC's two strong FRWs, and 7 faster than a PC's weak FRW. PC to-hit rises 4 slower than monster defenses.
These numbers don't take into account powers, Paragon paths, Epic destinies, or feats. This is just the raw effect of levels, stat increases, and enhancement bonuses of magic items.