I'm a unique breed, so answering that question is very difficult. It's not for environmental reasons, I can tell you that.
I'm a geek. That's my job, it's what I get paid to be. So naturally, I'm attracted to the technology of electric drive. It's a gizmo. It's unique. It's new. It's exciting. If I can afford it, I love playing with technology. If I can actually come up with reasons to justify my purchase, it's even better.
There are also political reasons. In the past 5 years, I went from being a warmongering neoconservative to a peace loving libertarian- a drastic change in my life that has in fact altered my appetite for oil. Part of my concern is recognizing that electric drive has the potential to free many Americans from their moral responsibility of not just financing undesirable characters in the middle east (tyrants and terrorists), but also creating demand for foreign interventionism, and thus blowback such as events like 9/11.
But being a libertarian, I'm also big on self sufficiency and independence. Electricity is a lot more plentiful in this nation than gas is. So in my view, relying on something that we have to ship over from half way across the world (or relying on something whose prices and availability are decided by people half way across the world who happen to not like is) is a lot less desirable than relying on something that is generated from stuff that we have a lot of here at home. But at the same time, I recognize that there really is no realistic replacement for hydrocarbons in our economy.
Then there are economic reasons, which are admittedly the most difficult to accept since batteries are so freakin' expensive. But the fact is this car does pay off in the long run assuming these high gas prices don't go away compared to cars similarly equipped.
So, those are my reasons. I'm probably missing a few. But in short, pure electric drive is much more interesting and appealing to me, if not practical for my commute.
Summary: To me, the LEAF is cool. The Prius most certainly is not.