Being a big fan of the LOTR books myself, and feeling that the films' screenplays and direction were both utter schlock, it occurred to me that this particular motivation may not be conducive to doing your best work! I was a fan of his previous films, which seemed to be done for the love of it.
We all try to gain pleasure and avoid pain. Most of us will work harder to avoid pain, though, making it probably the more powerful motivator. However, letting it take too large of a role in your life means your quality of life is negatively affected because of living in constant fear. It becomes a habit, which helpfully probably keeps you alive, but it does this by making you extremely risk-averse which also precludes future success! You may not want to do anything new.
One example of how letting pain-aversion become dominant affects you is that you may become extremely lazy. Let's say you've already got enough money that you don't have to do anything. Well, work requires effort, and effort requires energy expenditure, and that may involve some pain!
Of course previously you may have been excited to do the same kind of work, when doing it was about gaining pleasure. We tend to behave according to habits, and I would suggest it's not good to let yourself accidentally become habituated to using fear as a motivating factor, because it will creep into all facets of your life.
So, very recently, I have consciously been trying to not react with fear and panic in situations where I normally would. There are so many situations that are really no big deal, except for the mental model we use which we have trained ourselves to freak out over.
I'm getting to think that the majority of our large-scale behavior is due to unconscious decisions, and that we decide very little of importance consciously. So, in order to effect change, we may need to train and condition our unconscious via emotional responses. Almost like Pavlov-dogging yourself, do multiple things you already like in conjunction with some other behavior and you reinforce it: E.g. playing music and drinking Coke while hanging out with friends at the same time you're coding will reinforce your love of coding. Constantly think of negatives while coding and pretty soon you won't want to code on that project anymore, and maybe at all for a while!
I know this sounds cheap and gimmicky but I think it's very likely to be the case that our strings are pulled by our unconscious. See the Precognitive Carousel: http://everything2.com/index.pl?node_id=1422464
Also see this book on NLP (some of the formatting seems off from OCRing): http://www.scribd.com/doc/1984/Neuro-Linguistic-Programming-Using-Your-Brain-for-a-Change-Richard-Bandler-NLP
If you don't have a plan for your unconscious/subconscious drives, you can bet others do -- advertisers, religious and political leaders, and random authority figures will try to use pain (mostly) and pleasure to get you to feel like behaving the way they want you to.
I'm aghast when I realize how much of my childhood was actually a job as a field sales representative for Mattel. They recruited me via television cartoons (ads) to direct my parents' income to their revenue stream, in exchange for various "goods" now seen only on Robot Chicken.
(World of Warcraft is the new Mattel, and they are Skinner-boxing away years of people's lives.)
By the same token, when you as a founder are rich enough to never have to work again to maintain your previous standard of living, you'll find all sorts of expensive toys pushed on you, playing on the same ingrained habits from your childhood. You've been trained to be fearful so that someone can sell you a temporary band-aid. (There are evolutionary reasons why it's easier to push people toward fearfulness and pessimism -- ice age conditions were harsh! The constant worriers didn't have much fun, but they stayed alive. We're the descendants of people who got up and checked that the cave door was locked 57 times a night so sabretooth tigers didn't eat them.)
TV advertising now has two main themes: 1. "Look at these hot chicks -- now buy our product!" And 2. "You're not buying our product? No wonder hot chicks don't want you, fatass." Survival is a given in our society so the next most monumental drive is reproduction. Watch how many people who want money from you try to play on this. Don't be manipulated into fearfulness and insecurity.
If you're still young, try to be aware of when something is having an effect on how you feel about something. If you can see how your feelings are starting to change on something, you may be able to counteract it before a pattern sets in. If you're older, you probably have to un-do a lot of stuff that's conditioned you without you even realizing it.
"[They already had implants in their brains, and he] gave them a slideshow to watch, with a button to push to advance to the next slide. But the button was fake. What really moved the slide was a motor potential building in the brain before they were aware of the desire to move it. It unnerved the patients, because it seemed to them as if the projector was always advancing just before they'd consciously decided to advance it."
I think all entrepreneurs exist with both motivations constantly in flux.
Once you've gotten your feet wet and have seen some return, you probably start to switch into the higher gears.
I'm not in this to cash in the company. I'm in this to build a company I want to work for. Maybe that counts as "joy of victory."
I'm not afraid of failure; the last time I tried this, I failed. I'm being smarter about it this time.
After experiencing the freedom of working exactly the way I want to (through the night, sleep during day, days off if I need them), it feels me with huge dread to think of going back to answering to a 'boss'. Ugh.
So I guess I'm more heavily weighted in the fear of losing my current freedom.
IMHO, it's much more critical a question as to how one deals with the pressures that come up over time. I.e., do one's anxieties drive dysfunctional behavior -- is the stress used as an excuse to assuage one's own anxiety to the detriment of the play or is it used as indicators of factors that need to be addressed or what?
...I'm driven by the joy of creating something that I can use on a daily basis. Also a bit of a fear that I'll look like an idiot when I've already told 15-25 people about what I'm working on. And now I've gone and told all of news.YC. Crap...I guess I should get back to work then :P