How can I export all item ID's, Metadata and Names?

Not Enough Items can help you create a data dump. Launch your Minecraft, and go into a world. Access your inventory and go into the options (bottom left corner). Go to Block/Item settings, and create the dump by hitting "Dump ID Map Now". The dump will be created at your .minecraft folder. Open the .txt file and it will show you all the blocks loaded at the time of dumping.

You will see something like this:

Block. Name: tile.stone. ID: 1

It does not display metadata.

I have created a mod, ItemDumper for 1.5.2, (and for 1.4.7) to serve this purpose for you. It is pretty hacky, I wouldn't recommend you keep it loaded while just playing.

Install it in the usual way.

When you log in to a world it will dump out all the ID's, metadata, name and tool tip, in the form <id>:<metadata> = <name> = <tooltip> into a file called "ItemDump.txt" in your current working directory, (for FTB, this is the folder specified as the start up path, in the launcher).

Sample output:

...
688:0 = Monazit Ore =  Monazit Ore (#0688)
690:0 = MFFS Control System =  MFFS Control System (#0690)
900:0 = ME Cable - Blue =  ME Cable - Blue (#0900/0)
900:1 = ME Pattern Provider =  ME Pattern Provider (#0900/1)
900:2 = ME Controller =  ME Controller (#0900/2)
900:3 = ME Drive =  ME Drive (#0900/3)
...

The tooltip is probably useless.

Note that it doesn't catch all the different metadata values a item can incure from being damaged. Only those that can be spawned (by search) in creative mode.

The source code, released under MIT License.

It has at least one bug. It does not dump the ID's for any items that do not show up in the Creative Mod, item search. This includes, for example, Forge MultiPart blocks. At somestage I may fix this, I would need to work out how NEI gets a list of items. I suspect there is some kind of second Forge item list.

_{Thanks to Gunther Struyf , for compiling and uploading the 1.4.7 version.}