Many have answered this question and many have asked me the same… So after research from various sites including http://silverlight.net and http://blogs.msdn.com/ this is what I conclude:
| WPF | WPF XBAP | Silverlight | Ajax.Net | |
| Client - OS |
Windows XP SP2 & Vista | Windows XP SP2 & Vista | Windows XP SP2, Vista, Mac, Linux | Any OS |
| Client – .NET FX |
.NET 3.0 | .NET 3.0 | Silverlight Plugin | Not required |
| Client – Browser | NA | Internet Explorer 6+ | FireFox, Mac Safari, Internet Explorer | Any Web Browser |
| Deployment | Downloadable Installer or ClickOnce | Runs in Internet Explorer secure sandbox | One-time install of Silverlight plug-in | Web Page |
| When to use | Programs that need access to Windows desktop files. | Intranet applications for Windows-oriented companies. | Rich Internet Applications for public-facing web sites | General-purpose public-facing web sites
|
| Disadvantages | Typically works on MS-OS only | Mostly internal sites for companies that use MS-OS. | Works on any browser but has limited functionalities compared to WPF, WPF XBAP | Lacks Richness in UI |
Guess this will be helpful in analysing situations where to use what!
Check this link too its having nice collection of WPF interview question which helps fresher as well as developer.
http://mindstick.com/Interviewer/QuestionPage.aspx?topicid=8&topic=WPF%28Windows%20Presentation%20Foundation%29/XAML
Thanks John, the links are really good ones.