Age of Empires - Bronze Age upgrades

The upgrade to the Bronze Age costs 800 . The number of upgrades available increases greatly after advancing to this Age, so you have to choose wisely. Keep in mind the strength and weaknesses of your tribe when making a choice. For instance, for Chosons it is well worth to go up to the Long Swordsman and Legion due to the +80 HP bonus. Minoan Composite Archers have a +2 range bonus. To see all differences between the tribes, look at the

This page does not only list up all upgrades, but also explain their uses and advantages.
Barracks - Storage Pit - Granary - Archery - Market - Dock - Temple - Government Center - 3rd part (Iron Age)

Barracks

Research Short Swordsman 60 HP 120 50	Upgrade to Broad Swordsman 70 HP 140 15

Description: These units are not an upgrade of the Axemen, but independant from that. Short Swordsmen are twice as strong as Axemen, so you should get this upgrade unless your gold reserves are running low (under 100).
Broad Swordsmen are not that much stronger than their weaker companions; if you have enough gold, go for Hoplites instead. They are a lot tougher than Swordsmen. If you have a lot of Swordsmen already, this upgrade is still worth the price and better than the weapons upgrade.

Storage pit

Metalworking +2 melee attack 200 120	Scale Armor +2 Infantry armor 100 50	Scale Armor +2 Archer armor 125 50	Scale Armor +2 Cavalry armor 150 50	Bronze Shield +1 piercing armor 150 180

Description: Do not research all armors, just the one that supports your combat unit of choice. Which units you should get is depedant from the tribe you have chosen.
Even though the Weapon upgrade helps your cavalry and your infantry, the Armor upgrade is not only cheaper but more important. Swordsmen and Cavalry both have little armor but a fair attack power. The attack of Hoplites is already very high without upgrades.
The second upgrade of the Archer armor is as important as the first one (if you have some archers), so get it!
The Bronze Shield will reduce the damage from Archers by 1, and since Archers do not do much damage, this upgrade is worth the price if you can afford it. It will make your Hoplites much more effective since Archers are their worst foe. Get them!

Granary

Medium Wall 300 HP 180 100	Sentry Tower 150 HP 120 50

Description: The upgrade to the Medium Wall is quite a costly one. You should have your defenses set up in a way that walls can be defended by Archers or Towers. Unless you have very long walls or surplus food, you should not get this upgrade. Of course this does not apply to Wonder strategies where you concentrate on your defense.
The upgrade to the Sentry Tower is a must since a War Galley has a greater range than Watch Towers and makes them useless. Even if you have no towers next to the coast, this upgrade still gives you a great advantage.

Archery

Improved Bowman 40 HP, range: 6 140 80	Composite Bowman 45 HP, range: 7 180 100

Description: These upgrades are dead-end technologies that cannot be upgraded further in the Iron Age. Considering that the Wheel is about equally expensive as the Improved Bow and that Chariot Archers are faster and about equally strong as Composite Bowmen, these upgrades are pretty useless! A good reason to get this upgrade is if your tribe cannot get Chariot Archers or if wood is scarce. Once you have researched the Improved Archer, it will be much cheaper than a Chariot Archer. You'll get twice as much attack strength for your resources with Composite Archers (compared to Chariot Archers).

Market

Artisanship +1 missile range +2 woodcutting	The Wheel +30% villager speed Chariots	Plow +75 Farm production
170 150	175 75	250 75

Description: Artisanship is like Woodworking, just a bit more expensive :-) It increases the amount of wood that your villagers can carry and the range of your shooters. Get it!
The Wheel is what the Bronze Age is about. This is the best upgrade you can get! It will speed up your production (especially wood) and allow you to get Chariots. Chariots Archers are the best Archers in the Bronze Age, and Chariots are much cheaper than Cavalry. This upgrade is so cheap and so powerful, it is the first one I get in the Bronze Age.
The Plow works like Domestication, increases the amount of food that is produced for new farms, but not for the farms you already have. You should get it when wood is scarce. It is a good upgrade, but costs a lot of food.

Dock

Fishing Ship 75 HP, +5 capacity 50 100	Merchant Ship 250 HP 200 75	War Galley 160 HP 150 75

Description: The upgrade to the Fishing Ship is quite a bargain because the efficiency will be increased by 25% and the hitpoints by 67%.
Upgrading the Trade Boat to the Merchant Ship is pretty useless, though. You gain 50 HP, and the new Ship will be a bit faster, but that's all.
The War Galley rules the sea in the Bronze Age, being twice as strong as a Scout Ship. On sea maps, this is the #1 upgrade! Make sure you can get it (together with the Wheel) as soon as the upgrade to the Bronze Age is finished.

Temple

Astrology Conversion 30% faster 150	Mysticism Priest HP doubled 120	Polytheism Priest 40% faster 120

Description: The Temple is one of the new Bronze Age buildings where you can train Priests and upgrade them. Priests can heal your guys and convert enemies. You should have at least two Priests who can heal each other; otherwise, they are not very effective.
Astrology: Being able to convert enemies quickly is usually the difference between a successful and a failed conversion. Even though this upgrade is expensive, it is well worth the price.
Since Priests die like flies, you should get Mysticism as soon as you have two priests.
Polytheism: Priests will stand still when converting enemies, so this upgrade is not so useful for defending yourself. You should have it if you want convert towers. Just one question: in which gods believe your guys before you get Polytheism ;-)

Government Center

Nobility +15% HP for Cavalry, Chariots, Horse Archers 175 120	Writing Shared exploration with allies 175 120	Architecture -33% construction time +20% HP of buildings 150 175

Description: Unlike all other buildings, this one serves for upgrades only. You cannot train troops here, but you can build several Town Centers if you have a Government Center, which is enough to justify this building. More Town Centers let you produce more villagers and can serve as a Granary and a Storage Pit in one.
Nobility is not very useful. You gain little, and you should use your Cavalry against Archers only. Chariot Archers should avoid direct combat so the upgrade is useless for them, too. Get this upgrade if you have a lot of Cavalry units.
Writing is great in multiplayer games. It lets you coordinate your actions much more easily. In many games, good scouting makes the difference between winning and losing, and this upgrade improves your scouting a lot.
Architecture will help you a lot when defending your town, and if you have forgotten to construct a certain building, this mistake will no longer be as serious as before. This upgrade is a must for any defensive strategies (particularly Wonder strategies) since Wonders take forever to build. Your houses will also last one shot longer against catapults, which makes Architecture well worth its price.

Special thanks go to Mr. Grinch for his great tips.