Adblock Plus is an improved version of Adblock with a better user interface, and interfaces better to filter subscriptions so that your own filters and multiple subscriptions will not interfere with one another. Adblock Plus: Element Hiding Helper is a companion extension for Adblock Plus designed to make creating element hiding rules easier and is invoked from the Adblock Plus button's context menu.
Hosts File is a file not an extension, it blocks ads, banners, 3rd party Cookies, 3rd party page counters, web bugs, and even most hijackers. The hosts file contains the mappings of IP addresses to host names. This file is loaded into memory (cache) at system startup, then the system (Windows/Linux) checks the Hosts file before it queries any DNS servers; and, bad domains are blocked and will not be seen. Hosts file blocks some things cannot be blocked by extensions. A hosts file provides cross-application protection, regardless of what Firefox profile is used or what browser is used, or other applications accessing the web. It should be considered as a primary protection against malware and prevalent major annoyances, but usage is not very flexible as it relates only to a host domain. Adblock Plus provides more flexible filtering to deal better with annoyances than it does with malware, Both types should be used along with Anti-Virus protection.