I'm a C# developer looking to branch out. I want to try either flex or flash. Any recommendations on which to go with and why?
Silverlight! :D
Seriously, if you already know C# and you want to leverage that for rich internet applications, that's your best bet.
That said, if you're wanting a programmer-friendly non-C# way of doing things, I'd recommend Flex over Flash. Flash is..... shudder.
This link might help you in your decision.
I thing a good analogy to your question would be saying "I'm thinking about trying something new, should I learn how to bake or ballroom dance?"
Flash is primarily a client building thing. It has lots of hooks and bells and whistles, but at the end of the day 98% of what you build is sitting on a client and displaying stuff, not running on a server.
flex is, on some level, an alternative to things like JSP.
Commercially there's a lot of need for Flash, while Flex is just catching on. So, that might influence your decision making to some extent.
I gotta argree with Dr. Dredel. It's really hard (not impossible) to access databases and other server side stuff in flash. I took a flash class in high school, worst 18 weeks of my computer life.
Flex is a framework for Rich Internet Application development. It extends Flash with controls and namespaces for UI, data, etc.
If you want to venture a little out of your comfort zone, experiment with Flex. If you've ever worked with WPF it will feel familiar. If you want to get really wild and crazy, add Flash. You can combine Flash assets with Flex projects to create some visually zingy applications. It's worth experimenting with both to get a feel for what they can do together, which is quite a bit. Flex Builder is a good tool for both Flex and ActionScript projects.
I encourage you to try Silverlight as well, since you already have the C#. Both platforms have lots to offer.
You guys are forgetting that Flash is installed on 98% of all computers, while not even Bill Gates himself knows how many computers Silverlight is installed on. You should keep your audience in mind when deciding on what platform to experiment on. Also, remember that linux does not support Silverlight.
I don't know about you, but whenever I see a site asking me install Silverlight I'm instantly gone. One rich-internet browser extension is good enough for me! Honestly, why does Microsoft always try to reinvent the wheel?
Wow, it almost sounded like I'm a Mac-freak there... scary.