Please, please, please, please, please, please, please, do not use Flash unless you have to.
When? Web applications might need Flash. Movie players use Flash. A powerpoint-type presentation might need Flash. In which case, I will unblock it.
I watch animated GIF ads all day long (because I can pause them if they are annoying). I can’t do that with Flash. (Which is why I block it by default.)
So please, don’t use Flash unless you need to, otherwise you might be blocked unnecessarily by your visitors! For instance, I don’t want the banner of kirupa.com to be Flash, because I want to see it, and it doesn’t need to be Flash. I’m not going to click on the logo however, if it was Flash… it’s just not important. Looks great as a GIF. If you’re making ads, you will always get more impressions with GIF than with Flash due to visitor blocking.
(If you don’t know what I mean, that’s OK. It’s an old battle. 
I’m programming a new racing game in Flash right now. The OOP is great; ActionScript is easy because of this.)
GOLDEN RULE: If you’re making a website, ask yourself if the content is the text or the images. If it’s the text, do not make it 100% Flash, or require it. If it’s the images, 100% Flash is fine.
Agree? Disagree?
