Halo: Combat Evolved/Blood Gulch
Blood Gulch is the standard multiplayer map. It is a symmetrical boxed canyon with two bases on either side, and a "no man's land" between the two. There is an open cliff on one side of the canyon and a cave-riddled cliff on the other side.
The PC/Mac version of Blood Gulch is slightly different from its Xbox counterpart. The caves contain a Flamethrower and there is a Fuel Rod Gun in the center of the map. If enabled, the PC version also contains Rocket Warthogs and a Banshee at either base.
Blood Gulch is best played as a 16-player Capture the Flag game. It also makes for a good Slayer competition. Blood Gulch has often been called the best map in multiplayer Halo, as it can be played on any game mode with any game settings.
 Capture The Flag, Iron CTF, CTF Pro
 Standard weapons and vehicles
In the standard Blood Gulch layout, each team has two Warthogs - one with a machine gun and one with a rocket launcher. Each player has an assault rifle and a pistol. At the start of the game, almost every player's first instinct is to get into a Warthog and attack the enemy base. This is not the best strategy. Station two men on defense, and put one person in the machine gun Warthog. Send that Warthog to get the enemy's flag. Put two men in the rocket warthog and park them to the side of your base to be used when enemy 'Hogs launch an offensive.
The key to winning at Blood Gulch is keeping your enemy spread out in the field, while you launch offensives at their base.
 All weapons and vehicles
From the start, send some guys to the middle of the stage, in between both teleporters with a Scorpion. Then send one guy to take Sniper Rock and another to get the Flamethrower. From there, send your best players forward to try and capture the Enemy flag. The Sniper should provide excellent cover and can spot enemy forces with ease. The Flamethrower guy should just hold his position while killing anyone that comes for it. Your flamethrower user should be the worst player on the team. If any enemies come through the teleporter, you can easily use the Scorpion to blow them up. If you can afford it, have one guy defend your base, just in case anyone gets past your Sniper/Flamethrower and Scorpion. Just keep up this strategy and hopefully you can win. Be careful of Warthogs, however, as your Scorpion and Sniper will be too slow to get it, which is why it pays to keep one guy at your base.
 Team Slayer
There is no real strategy for Slayer. Just send some guys to the center of the Map with some Warthogs or other vehicles while sending other people to get the Sniper and Flamethrower. Have your Shotgun user(s) stand at the back lines. Have your Sniper provide cover and have your Flamethrower defend his position. If you have any more troops, just use them as you will.
 Slayer, Slayer Pro
Every man for himself. No real tactic except for getting the Sniper and Shotgun and get any powerups you can. Get the Scorpion as quickly as possible and bail as soon as it's about to be destroyed. Warthogs, if you can get to them, can be used as stationary turrets or steamrollers. If you are using a 'Hog as a steamroller, your best bet is to circle one of the bases, squishing people.