ICBM is ageing now and there's no new insane defence mods for Minecraft. Poenjabiesous (pretty wacky name eh?) aims to fix this with Modular Turrets, an addon for Thermal Expansion that gives us Turrets, and then some (well...alot more). Get yourself a base, get yourself a turret, and mix and match the whole shebang with different amounts of turrets, upgrades, power inputs and even ammo in some cases, on a single base block. Truly modular. I showcased the Modular Furnace mod about a year ago when it first came out, the mod blew up in popularity, I hope the same happens here.
Stick this in your modpacks people!
Check the mod out here, bear in mind it currently only supports Minecraft 1.6.4, however the mod author is currently at work developing and porting the mod to 1.7 (thermal expansion 4 has been changed pretty significantly in 1.7 so this is probably causing the delay):
Texture Pack (sphax pureBDcraft): http://bdcraft.net/purebdcraft-minecraft
Twitter (I answer all of your questions!): http://twitter.com/JANKYnik
Link to download Forge (required for the mod to work): http://files.minecraftforge.net/
This mod is forge compatible, so you can therefore put it on servers, and is super easy to install!
TO INSTALL FORGE:
Choose the 'Installer' option under your Minecraft version (in this case 1.6.4) in the 'All Downloads' section, then open the installer and choose to install the client. Once this is done close the installer, open the Minecraft launcher and in the bottom left corner drop down menu select 'Forge'. Run Minecraft once and then close it again. Next download the mod and place the mod .zip in your Minecraft 'mods' folder (located in your .minecraft folder).
Then run Minecraft again under the 'Forge' profile and you're good to go!
After this all you have to do to install any other Forge mods is put those mod .zip files in your Minecraft 'mods' folder.