Your question is a bit border-line, as it essentially asks for our opinions. Instead I will discuss what some philosophers have said about this.
Let's, for the sake of the argument, assume that wealth indeed implies well-being, and that therefore wealth is desirable. I will also use rich and wealthy as synonyms, as I will use poor and unwealthy.
Then, we could say that the maxim we want to know if it's an element of or derivable from the ethics of certain philosophers, would be:
Act such that your actions will converge inequalities in wealth between all people as much as possible.
Now, let's see what Kant would say about this.
Kant's famous categorial imperative says, in the first formulation:
Always act according to that maxim whose universality as a law you can at the same time will.
– Immanuel Kant, Foundations, p. 436
There are two other formulations, but here, especially the first formulation is interesting. On wikipedia, the universability test, a method to determine whether or not your maxim can be one of those of the categorial imperative, is described.
Let's imagine a world in which the maxim as we defined it is a universal law. Therefore, everyone necessarily acts according to this maxim. Do we find a problem here? No, rather the opposite:
If everyone would act according to a maxim as "act such that your actions will diverge inequalities in wealth between all people as much as possible", the world becomes terribly unstable.
First of all, this will create one group very rich people and one group very poor people. However, in the end the rich people will need the poor to be richer in order to get richer themselves (to sell things, to produce more, etc.) So in the end we can't diverge anymore. Any action to make the rich richer will need the poor to be richer as well; any action to make the poor poorer will need the rich to be poorer as well. We're running into a state in which the maxim doesn't really have any effect anymore: a final state, in which people can't really follow the maxim to its end anymore. The question is whether this final state is desirable.
Secondly, imagine some kind of natural disaster, somewhere along the way to this final state. A big flood comes, destroys everything of the rich, making them poorer than the poor. Following the maxim, the 'old poor' will now become richer and richer, while the 'old rich' become poorer and poorer. This demands adaptability from us, the humans in the world, an adaptability that we don't really have.
So a world in which the opposite of our maxim is a universal law, isn't desirable. Kant doesn't say that from this follows that the maxim itself should be a universal law, but it could be argued with his help.
The immoralist. He didn't really formulate his own ethics, but had lots of criticism on others. He argued that 'God is dead', meaning that we don't have any moral framework anymore, and that we're "plunging continually":
Whither are we moving? Away from all suns? Are we not plunging continually? Backward, sideward, forward, in all directions? Is there still any up or down? Are we not straying, as through an infinite nothing? Do we not feel the breath of empty space?
– Friedrich Nietzsche, The Gay Science (1882, 1887) para. 125; Walter Kaufmann ed. (New York: Vintage, 1974), pp.181-82.] (http://www.fordham.edu/halsall/mod/nietzsche-madman.asp)
It's a madman talking here, but it's assumed that Nietzsche referred to himself. In the end, the madman leaves:
Here the madman fell silent and looked again at his listeners; and they, too, were silent and stared at him in astonishment. At last he threw his lantern on the ground, and it broke into pieces and went out. "I have come too early," he said then; "my time is not yet. This tremendous event is still on its way, still wandering; it has not yet reached the ears of men."
Nietzsche of course doesn't really tell you what to do in this case, but he complains about there not being a (universal) moral framework. With Nietzsche, you could therefore argue that making any maxims yourself is pointless as long as they're not universal. Furthermore, you could say that making a maxim universal would require more than a human, and therefore that making maxims yourself is always pointless (because you can never make them universal). It would require a God, to make maxims, but unfortunately, God is dead, and we can't get him back.
I find the explanation of his thought on the Dutch wikipedia much clearer than on the English one, so I will translate a bit:
The postmodern society lost its belief in bigger contexts such as explicit ideologies, authority, religion, tradition, etc. In Lacan's terminology, the Other (with a capital), is the overarching justification of social order, death. This leads to social disintegration. As progressive thinker he doesn't regret every break with tradition, but he sees a couple of interesting, or alarming, effects of the lack of a social framework.
This last sentence is of course very much in line with Nietzsche, and Žižek also says, like Nietzsche, that this lack of a social framework is alarming.
Maybe now it's the time for Nietzsche's madman, in the form of Slavoj Žižek.
A way out from this lack of framework is not discussed as far as I know.
One could argue that you asking this question in the end is an effect of the lack of a moral framework, and that therefore your question "Am I immoral for ever spending money on the movie ticket?" doesn't make sense - there is no such thing as immorality.
Some loose thoughts
Spending money on a movie ticket may make you much happier so you become more productive, earn more money, and can give more money to charity in the end. It's not as black & white as it may seem.
How much of your donation will end up with the people needing help?
What is good help in this case? Should we try to help people get wealthier [knowing that this will take several generations, if we're ever going to succeed], or should we try to help the people that are alive now by social support, "being there for the other", etc.?
How much effect is your money really going to make? For $1000 you can feed x hungry people, who will then die one day later. For $1000 you can also travel there yourself (for example), talk to the people, give them this experience (being listened to) that they will never forget, and give them strength for the rest of their lives, albeit short.
You state that you think you're morally obliged to help less wealthy people. Yes, this does mean spending money on things you're not morally obliged to spend money on, would be considered immoral. However, I've been trying to point out that this moral obligation is not so clear-cut.