PDF-XChange PDF Viewer 2.0

With a really good looking interface, multiple language support and lots of features, this viewer is aiming to become the new PDF viewer standard, dethroning the Adobe Acrobat.
A very important detail is that this application you can use it legaly without spend a buck since its a freeware.
You can upgrade to the PDF-XChange PRO that is much more than a viewer, it also allows you to edit your PDF documents with professional tons of tools.
Tracker Software Products – the developer – also offers a portable PDF-XChange Viewer version. With a 4 MB file size can be run from memory cards, CD, DVD and others devices alike and doesn't require installation.
The quality of the product is guaranteed if you take a look to its Help menu. It displays the following options:

Report a problem...: this is great because the whole users community is acting as a big debugger team, detecting failures and reporting them so the developer can solve the problems.
Check for updates...: related to the previous option, from here you can always access to the newest version of the software wich includes patches for all the problems reported so far.
Support forums...: if something comes along and you don't know how to do, you can visit the forums to know the “popular wisdom”.

As a viewer, a remarkable characteristic of this one is that supports multi-tab styled browsing of multiple documents. Nothing more annoying when you have to work with more than one document at a time that a lot of viewer instances open. This way, like new Internet Explorer or Firefox web browsers, you have a tab per document all within a single window. Much more comfortable and faster.
A couple of really cool tools need to be commented. The sticky notes tool is one of them. By clicking on the document, wherever you like, you can tape-up a virtual sticky note to remember something. That's not all, you also can set a lot of properties for it as transparency, color, icon, etc.
Another cool and easy-to-use tool is the stamp tool. With a stamp like icon you just mark your documents after a predefined texts such as: Approved, Final, Draft and much more.
As simple as that you can draw geometric forms as well. With a very accesible toolbar you can draw lines, rectangules, circles, arrows, polygons and else.