Real Value of Objectives
Often times, I become so frustrated when my team has an opportunity to take a free Baron but end up wasting it because everyone wants an Outer or Inner Turret. While it is arguable that an Inhibitor Turret may be worth just as much as a Baron, Inner and Outer Turrets, without a doubt are worth much less gold than a Baron Buff. Additionally, Dragon is often given up in favor of an Outer Turret, though Dragon is arguably worth equal to or even more than the Turret.
Rewards of destroying an Outer Turret: 100 Global Gold 150 Gold split between players who participated Slight Map Pressure Total Value: 650 Team Gold
Rewards of destroying an Inner Turret: 125 Global Gold 100 Gold Split among players who damaged the turret 30 Global Experience Moderate Map Pressure Total Value: 725 Team Gold, 150 Experience for Team
Rewards for destroying Inhibitor Turret: 175 Global Gold 100 Global Experience High Map Pressure with exposed Inhibitor Total Value: 925 Team Gold, 500 Experience for Team.
Rewards for slaying the Dragon: 25 Gold to slayer 8% extra Attack Damage and Ability Power on First Kill 15% extra damage to Minions and Monsters on Second Kill 3% extra Movement Speed on Third Kill 15% extra damage to enemy Structures on Forth Kill Double the above bonuses for 3 minutes on Fifth Kill and onward 75-300 Local Experience, Extra for low-leveled Champions Total Value: Various Permanent Buffs, 25 Gold, and 75-300 local experience.
Rewards for slaying Baron Nashor 300 Global Gold +25 to player who slayed Baron Nashor 600 Global Experience 800 Local Experience 40 AD, worth 1440 Gold per member 40 AP, worth 770 Gold per member Enhanced Recall Moderate-High Map Pressure Total Value of Baron: 1525 Team Gold (Actual), 11050 Team Gold in stats, 3000 Experience for team, 800 Local Experience.
Based on the calculations of the values of Dragon and Baron with the values of all Turrets, excluding Nexus Turrets, Baron is completely worth more than an Outer or Inner Turret. Of course, there are situations where going for the Inhibitor Turret is much more lucrative than Baron, such as while the enemy is ACE'd while on 30s+ Death Timers, when it is possible to end the game right there. However, based on the values of reward alone, if the enemy team is down but with a small death timer such as a 25s timer, it is definitely more viable to go for Baron.
When it comes to Dragon, however, Dragon is seldom worth more than an Inhibitor Turret and sometimes worth less than an Inner Turret, but nine times out of ten, Dragon is worth more than an outer Turret.
Update: Dragon is now usually worth more than any Turret except for the Nexus Turrets. The Permanent Buffs grant so much for the rest of the game that it's usually a better idea to take Dragon than a Turret.
Additionally, securing Baron technically gives double the gold lead. Because it is both available for both teams to take, if one team secures the objective, then that means the other team has "lost" that objective, meaning the discrepancy between the two teams is equal to the lead gained from one team plus the loss suffered from the other, essentially doubled the value of the rewards.
Of course, everything is situational, but I do hope this has put the value of objectives in perspective.