What is it that makes the iPod so dominant?

Anyone who's followed me here from my PC Doctor blog will know that I don't have an iPod and that I don't use iTunes.  Don't get me wrong, it's nothing personal.  I've looked at a number of iPods, handled a few and listened to a couple, but as yet I've never taken the plunge and bought one.  I've bought a number of portable media devices over the years (I like the Creative MuVo right now - it's small and I can power it for days on a few NiMH AAAs),  However, one thing that I can't fail to take note of is that the iPod brand is phenomenally popular, and that in not owning one, I'm part of a minority among MP3 users.  Whereas I've gone to a store and looked at one and walked away empty handed, a lot of people seem to be unable to resist the temptation.  I think that the things that put me off was the battery life (better now but I'd rather rely on AAA), restrictive formats and iTunes.

Yesterday CNET posted an editors' review of a new portable video player from Toshiba, the Gigabeat S.  While on paper it looks great, the reality is that it's unlikely to even make a minute dent in the sales of the iPod.  It's a pretty safe bet that six months from now we'll be saying "Gigabeat?  What's that now?"

So, my question to you is simple - What is it about the iPod that's made is such a dominant brand?  Is it the design?  Functionality?  Brand?  Fashion?  Price?  Marketing?  I'm stumped as to why, so I'm handing the question over to you. 

• If you bought an iPod, why did you buy it?  How many have you bought?  Would you buy another one? 
• If you're like me and not an iPod owner, then don't feel left out!  I've got some questions for you too!!  First off, why haven't you bought an iPod?  What do you use instead?  Do you have any plans to buy an iPod in the future?

As an aside, what are you're thought on anti-iPod marketing campaigns like the iDont by Sandisk?  Are they just a bit of fun or are they offensive?

You have the floor!