I guess it depends on what you want to do. I find Adobe Flash to be more user friendly for beginners since you can just drag and drop things where you want them to be.
However it seems there's not a lot of 100% flash sites out there, and probably for good reason. If you want to do things that are a little more complicated than how the site looks and feels, then you might need to branch out into more than just Flash.
And that's where HTML comes in. HTML lets you put a lot of things together, including flash objects. I personally use Adobe Dreamweaver since I got it with Adobe Flash. You could just use a notepad if you're a really fast learner, or I'm sure there's some freeware HTML editors out there with a little less (but acceptable) power than Dreamweaver to get you started.
I'm a beginner myself, but I'm a healthy ways into learning more. I hope my perspective helps!