闲话不多说，先从官网上抄一段简介。
The new Atmel AVR Studio 5
Atmel® AVR Studio® 5 is the Integrated Development Environment (IDE) for developing and debugging embedded Atmel AVR® applications. The AVR Studio 5 IDE gives you a seamless and easy-to-use environment to write, build, and debug your C/C++ and assembler code.
One environment for 8– and 32–bit
AVR Studio 5 supports ALL AVR microcontrollers. Now you can bring all your 8– and 32-bit AVR projects into one, easy-to-use environment.
+ Click to enlarge image
Integrated C Compiler
You no longer have to install a separate compiler or toolchain. AVR Studio 5 includes a compiler, assembler and a simulator, and interfaces seamlessly with in-system debuggers and programmers to make code development easier.
+ Click to enlarge image
New Project Wizard
Starting a new project is easy. In AVR Studio 5, the New Project wizard sets up all the compiler and linker settings, letting you jump straight to writing code.
Create a blank project, or select from several hundred example projects.
+ Click to enlarge image
A Better Editor
The AVR Studio 5 editor simplifies code editing and lets you code more efficiently. Type a few letters of a symbol, and AVR Studio 5 will display a list of suggestions. Type a shortcut to expand frequently used snippets of code. Instantly view the context and definition of a symbol just by clicking on it. Hover over symbols while browsing code to see related information. Get the information you need without hunting for it.
+ Click to enlarge image
Atmel AVR Software Framework
The AVR Software Framework is a collection of production-ready source code, written and optimized by experts and tested in hundreds of production designs. Using these peripheral drivers, communication stacks and application-specific libraries is the quick and effortless way to complete a project.
Software Framework works across all 32-bit AVR UC3 and 8-bit AVR XMEGA devices and works with both GNU and IAR C compilers.
+ Click to enlarge image
Standard APIs
The AVR Software Framework uses a set of standard Application Programming Interfaces or APIs across all AVRs. They simplify how your application code interfaces with chip peripherals and communication interfaces, ensuring that your application code migrates even easier across the whole range of AVR microcontrollers.
Application Builder
Use the Application Builder to import drivers, communication stacks and services from AVR Software Framework into a project. The Application Builder automatically manages library dependencies, making sure your code contains the required drivers.
Solution Explorer
The Solution Explorer presents an organized view of all your projects and their files, and gives you simple access to the commands that apply to them. You can easily create applications containing multiple microcontrollers and develop the code for all of them within the same solution.
+ Click to enlarge image
In-system programming
AVR Studio 5 connects seamlessly to a wide range of AVR debuggers and programmers.
One of the biggest advantages of modern flash microcontrollers is their ability to send debug data to your PC, giving you perfect view of what goes on inside.
JTAGICE3
The new JTAGICE 3 is smaller, faster and more robust than previous models, and supports all 8- and 32-bit AVR microcontrollers.
I/O view
With the JTAGICE connected, AVR Studio 5 can present status of all processor, memories, communication interfaces, and analog interfaces in nicely formatted views, giving you fast access to critical system parameters. There is no faster way to identify bugs and optimize a design, in the lab or in the field.
Easy updates
Fast in-system programming allows a software update to be downloaded in seconds. Self programming and custom bootloaders allows microcontrollers to receive code updates via any interface, even across a radio link.
官网简介就这样了，从我初步用的角度来看，首先最大的变化当让是IDE了，用的是VS2010的shell,如果电脑里安装了vs2010中文版的话这个界面也都是中文版。IDE的变化最爽的就是写程序，代码提示，用起来很爽。工程管理界面看起来也非常舒服。
当然也有不爽的地方，不爽一是安装包很大，需要.net 4.0支持，完全安装1个G的空间，安装时间也很长，这一点肯定是其他单片机类开发软件没有的，不过想想这也没啥，用的方便就可以。软件设置改动很大，需要一段时间来熟悉。
当然最郁闷的就是仿真器支持的少了，最便宜的JTAG用不了了，STK500倒是可以用，但是支持的器件要比在4.x的版本中少，我用的mega128就不支持。如果用jtagice mkII的话要五六百，暂时还买不起。只能用双龙ISP或者通过bootloader下载了，其他的地方正在琢磨。
最后给上下载地址：
这个下载地址是官方正式版的地址，包含所有的组件的版本，下载他没错了，也可以去官网下载，但是得先注册一下。
http://www.atmel.com/dyn/resources/prod_documents/as5installer-5.0.1163-full.exe
上面这个版本是20110511更新的，有兴趣的可以关注一下。欢迎交流。