Lunar Client An FPS boosting Mod Client, with all the mods below (excluding the whole of LabyMod and part of 5zig's features). No more do you need to find the mods, check if it's up to date, install the mod, and go through the process of reporting bugs. It's all there! It is available for 1.7 and 1.8
A very nice map that sits in your HUD. You can also set waypoints.
Customization mod to improve frame rate and other video settings.
Minecraft Forge A Minecraft launcher which can load mods dynamically without changing or patching the minecraft.jar.
LabyMod has a wide range of features that will make you want to use it, from toggle sneak to 1.7 animations it has a bit of everything. You can view their features on the website.
Toggle sneak allows you to stay in sneak mode without having to hold a button down continuously. Improved chat brings a longer scroll back, special characters, the ability to turn chat off/on, copy/paste plus click on links.
5zig is a ui for displaying useful information to you without having to enter debug mode, you can enable being able to see your current x,y,z, your direction and much more useful information!