Let me tell you few great things about magento..
Magento is perfect solution for e-commerce these days.. Many big banners are now running their webstores with magento ecommerce.
Magento is open source php e-commerce which is based on zend framework. Its a wonderful composition of OOP based mvc architecture. If you are not a developer just ignore previous lines.
There are lots of feature inside magento box which are perfect to meet your e-commerce desires. Even a single magento will able to handle your multiple sites, with multiple language options with just one admin. Managing Customers, Products, Categories, Orders, Shipping are strong part of it.
You have multiple choices with magento version selection. You can use open source version which is also called community edition. It is free of cost as well as you can purchase a paid magento version which comes with insurance of your ecommerce webstores.
Magento has just release its community - free edition - version 1.6.0.1 beta 1.
I am experience with magento since its 1.3.2.0 version was in market. So I have seen a lot of changes and improvements with its releases.
You can download magento community edition over here :- http://www.magentocommerce.com/download
If you are looking for its release notes and what new has been included or what improvements are given, you can visit this url
I am waiting eagerly for stable version so that I can use if for my clients.