From Whisper's Wiki

I have played a lot of Counter-Strike:Source on pub and in wars, and far too often people do not know where they need to plant the bomb in order to maximise the possibility that the Terrorists will win the round, and win the round without sacrificing their lives to do it. So I have provided these screenshots in order to illustrate what I think are the correct bomb planting locations for a given Map & Bombsite with a few short notes to explain the rationale behind choosing this location.

Bomb Planting

There is a simple principle regarding the position to plant the bomb which is:

The less cover you have when planting the bomb, the easier it will be to defend
The more cover you have when planting the bomb, the harder it will be to defend

The examples I illustrate below, show the bomb planted in the optimum position to allow the Terrorist team to defend the planted bomb with the greatest possibility of success, for the least amount of defensive risk, and the highest probability of survival if the bomb is allowed to detonate. More often than not, I provide the several options, but the first option is usually the prefered one, and I will include a few notes attempting to explain why.

When you play a war, you and your teammates should know exactly where the bomb is planted without even having to look for it, so if a CT does try and defuse the bomb, they automatically know precisely where to go without a second thought.

When you play pub CS:S by planting in decent defendable positions, you give your team a chance to win the round, which allows your team to have more cash which usually enables them to win more rounds and so on.

If you have better bomb planting options for the maps I have included, then let me know what they are and why.

Also feel free to include more maps if you wish.

NB: It is ok to plant the bomb in a hidden spot when you are the last person left, and you either have no idea where they are, or you know where they are, but also know they kill you if you try to plant out in the open.

Dust2

Dust2 BombSite A

This is the default quintessential Long A Bomb plant. Placing the bomb here keeps all of Long A in play as well as allowing the bomb to be covered from Short A Stairs. It is also positioned in such a way as no sneaky defuses can be done through any of the walls.

This is your typical Short A plant. The advantage of planting here is it takes any CT's at Long A out of play and if a CT tries to defuse, an eagle eyed Terrorist can kill them from CT Spawn.

Can't plant because Long A is covered, don't like option 2 because CT's can be coming from CT Spawn, well this is your final option for Dust2 Bombsite A. It still allows you to cover the bomb from Short A Stairs, and reduces the cover a CT would have if the bomb was planted a closer to the boxes.

Dust2 BombSite B

If you plant anywhere else in Bombsite B on Dust2 you are a deadset idiot. The bomb can be covered from just about every point around the bombsite when the bomb is in this position. I am at a complete loss as to why people would plant anywhere else if Bombsite B is captured, as CT backup from A is generally going to take a short period of time.

Cbble

Cbble BombSite A

If you have the time this is the place to plant the bomb. The bomb can be covered from mid-connector, the box at the bottom of the ramps, corridors, from behind the boxes inside CT spawn, and from within the bombsite itself.

Similar to Option 1, with a little disadvantage trying to cover from corridors.

The quick plant option with similar coverage to Options 1 & 2

The plant with cover option, without giving the defuser a ridiculous amount of cover.

Not so much cover while planting and not as many coverage options, but better than a lot of other spots

Cbble BombSite B

This is a great spot. You need to smoke or take mid connector for this position to be a viable option, but once the bomb is down you have cover options from almost all around the entire bombsite from, Mid Connector, Upper B, Back of B, B Corridors, the Grassy Knoll, and from on top of the boxes in B Corridors.

Not quite as good as Option 1, as it takes out the Mid Connector, but still keeps many of the other options in play.

Not very good but keeps you in cover from Mid Connector and still keeps B Corridors still in play.

Nuke

Nuke BombSite A

This bomb position keeps the maximum possible numbers of positions open for covering the planted bomb, including the vents, the hut, the roller door, and up the CT ladder. It is also interesting to note that you can easily shoot a bomb defuser through the wall of the hut.

Not quite as good as above, but gives the bomb planter a bit more cover, and still quite defendable.

Nuke BombSite B

This is almost the only option you have on Nuke in Bombsite B, as it keeps the side doors, both vents, the control room and the ramps entrance all in play.

Another view of the above planted bombs position.

Train

Train BombSite A

This position is the prefered position on Train to plant the bomb. It offers the Bomb defuser next to no cover and gives the Terrorists countless options to protect the planted bomb from, including: Electrical (E)-box, Little Ladder, Big Ladder, T connector, Vines, Mid Connector.

Another view of the planted bomb for Option 1.

Gives some cover, but brings the back of A into play.

This option reduces the options for bomb cover from the front of A, but still keeps the back of A in play

Same as Option 3.

This probably should have been Option 1. or 2. Lots of bomb coverage options from all over TrainYard A.

Train BombSite B

Best Option for this site when available. So many goblin spots for Terrorists to cover the bomb from it's ridiculous.

A slightly different slant on Option 1. but brings the top of B into play more.

Inferno

Inferno BombSite A

This position gives the Terrorists the maximum amount of coverage options, most importantly from CT spawn, where the Terrorist are far outside the bomb damage radius with the bomb perfectly in view.

If you can't use Option 1. because the CT's are covering from CT Spawn, then this is you next bestion option.

If CT spawn AND Banana is a problem then this is your next best option. Not the best spot but still gives you decent bomb cover options.

Inferno BombSite B

Plant here if you can. This puts Library, Pit, Balcony and the Terrace all in play, as bomb coverage options.

This position gives you a bit more cover and still keeps everything but the library in play as bomb coverage options, but does not take out the CT spawn side of the bombsite completely out of the equation.

Aztec

Aztec BombSite A

The only position you should be planting in bombsite A on Aztec. People who plant behind the box at bombsite A should be taken out and shot.

Aztec BombSite B

This position keeps the T double doors, CT double doors and the CT bridge room side exit all in play as bomb coverage options.

Bomb planting position if you are worried about incoming CT's from CT bridge room side exit.

Bomb planting position if you are worried about incoming CT's from T double doors.

Dust

Dust BombSite A

Optimum position for bomb planting position for Dust BombSite A. Can be covered from dark corridor, anywhere inside the bombsite and most importantly from the CT ramp!

Not a prefered position, but due to its location, CT's can find it difficult to locate the bomb when it is planted here.

Dust BombSite B

This position allows the bomb to be covered all the way down at CT mid as well as from any position at or near CT spawn and within the bombsite itself.

This position gives you a bit more cover whilst still providing options to kill a bomb defusing CT.