It seems to me that super-villains want either of two things:
World domination; or Immortality.
Now, the first one I can understand. Being the Master of the Universe certainly sounds attractive, and while the geopolicital considerations may be a little stressful and some of the administrative details rather tiresome, the advantages gained from this position would undoubtedly outweigh the disadvantages. Personally, I'd much rather lead a quiet and happy life in a reasonably-sized house and be pleased with my lot, but I still fully understand the prospects that motivate Evil Overlords.
But immortality?! Living forever is serious business, and if you were to invest all your energy and years of planning into achieving this, surely you would spend some time comparing the pros and cons of eternal life. And so, you would inevitably reach the following conclusion: Being immortal is the most horrible form of torture ever conceived. I'll dedicate this post to explaining why I believe this is true.
Now, don't get wrong. Longevity certainly is cool. There's nothing wrong with living a very long time - there's something wrong with being unable to die.
(For the sake of clarity, I'll define "Immortality" and "Eternal life" as "The quality of being unable to age or die, combined with the ability to gadually regenerate any part of your body." The regeneration ability is added in order to avoid uncomfortable questions such as: "Are you still alive after your head has been smashed into 227 seperate peices?")
Let's first look at things from a practical point of view. What is realistically going to happen if you are granted immortality in real life. How you want to spend the first 10,000 years of your existence is up to you. Abuse your immortality to become rich and famous; learn everything there is to learn about Mathematics, Psychology, Physics, English Literature, Economics, Computer Science, Biology, and so on; master every musical instrument on the planet, every language, every martial art; achieve your childhood dreams; read every book that is worth reading... the list goes on. If we assume the human race don't somehow destroy the planet withtin the next million years, you will also get a chance to see a world in which animal species look rather different than the ones present on Earth today. By that time, life in general will be so radically different from the present, that we can't realistically predict what you'll be doing to pass time. Due to the increase in solar temperatures however, the Earth will become uninhabitable, so you will have to leave if you have not already done so.
My guess is that you will begin felling bored sometime during the following 100 trillion years. And by "bored", I mean of course "unbearably, mind-numbingly bored". Unfortunately, this is just the beginning, and things are about to get much worse. Indeed, around that time, the Universe should slowly start to be hostile to life in general, as the stars go out. Then starts the decay of the Universe. If your lucky, time-space will eventually collapse unto itself, and everything will be compressed into a dimensionless singularity, thus effectively putting an end to your existence. If you're unlucky, the Universe will "end" in Heat Death, and you end up floating around aimlessly in a universe that consists entirely of nothingness. The trillion years you spent among a universe that supported life, will seem like a quick flash compared to the eternity that you will spend in this miserable state. Enjoy.
There's a very entertaining piece of fictionon the Net that illustrates my point. I do, however have one issue with this story. It puts too much focus on the problems of living a long time, and being part of a lifeless universe. Granted, these are important factors in making eternal life a living hell, but that is not, in my opinion, what makes immortality such a curse. The problem, I want to emphasise, is that dying is impossible.
So let's examine things from a more theoretical perspective. Suppose that, after your physical death, you gain Eternal Life, and enter a wonderful place that is perfect in every way. No universal collapse, no heat death, no exploding stars, or anything like that. Everything stays impeccable. Why do I still claim that this heavenly immortality would be worse than purgatory?
Because, as I mentioned earlier, you get bored out of your mind. It might take a long time, maybe some people can manage to keep themselves occupied a quintillion years, who knows; but even a quintillion has an end. After that you will already have done everything that you can possibly do, seen everything there is to see, learnt everything there is to learn, and you've done it so many times you can no longer keep track of the numbers. Any newly published book will look completely identical to one you've read a thousand times. If a few things still amuse you, you can practise them an indefinite number of times, but there will always be a moment when the feeling of enjoyment fades away. What's worse is that, while your initial period of happiness will have lasted a finite amount of time, the boredom will last eternally. Maybe you'll try pain, just to experience something new, but even that wears out. Suicide is, fo course, futile. Every morning you wake up, and have to go through another day you've already experienced. And the next morning you will wake up again. And again. And again. And again. And again. And again. And again. And again. And again. And again. And again. And again. And again. And again. Madness is bound to ensue, but even so, it never ends. I think I have made my point. The worst part of being immortal, is not that you outlive everyone else, not that you cannot stay on Earth, not that you burn for billions of years inside stars, not that you get bored quickly, not that you get bored after a long time... the worst part is that you cannot die.
Go for world domination, then.