An application that would analyze stock and option data on the fly to determine when to buy and sell. It would also do the buying and selling for me. Since everyone cannot make money in the market, this application would be for me only (I'm greedy).

The reason for wanting to build this application is for two reasons:
1. Having money is nice .
2. I have been interested in the stock market since the age of 8.

I would create an automatic carmoving system to control all cars in the world, based on an realtime Google Map API with live traffic data, so no one has to drive anymore, and we could move ourselves at 300km/h, because the system can precalculate where to move and which cars he passes.

I think I would build a collaborative tool for enterprise users with features like: email client, employees search/info, knowledge repository, sharing (documents, files, presentations), videoconferencing, chatting, calendar, appointments, meeting room reservations, etc.

Reasons:

1. It could be a killer app
2. I could use it with my colleagues of Undefined
3. Integrates a lot of technologies and features in one application

I would build a system for real collaboration that organized everything digital together. It would include tools for helping make digital content and interesting ways to get at and find information. The most important part would be it's flexibility, it would have to be able to accommodate everything that could be created digitally now and in the future. I'm thinking everything from organizing governments content to allowing artist to work in real time together. Communication tools like Google Wave are cool but I'm talking about actual creation of content (not just text) in really time while organizing this content with meta data so that everything is more accessible to anyone interested in seeing it. If the system became large enough it would act like a layer on top of the internet, organizing everything into a hierarchical system and allowing people to create content for that system easily.

Reasons:
It seems like where things are going already, I would like to push it there.

I would like to build a web application wich scans all existing websites, indexes the content and makes it searchable via a website.
I think there are so many websites out there with so much information, it would be good to have access to all that data.

Perhaps a blog or a even a guestbook?

Well, I built an RIA for corporate recruiting - easy-to-use, sick analytics, collaboration, project management, a global workflow.

Now.. I would like to build easy-to-use SFA software. Salesforce is bunk. Sales people constantly complain about it. It would be fun to moon the giant.

Skynet

The Matrix

I would build an app that visually displays availability of basic services (primary health care, clean water, education, electricity etc ...) throughout the world based on data gathered with the limitless resources. Think layers of data over a map.

Then, with the rest of the limitless resources, I would work on eliminating need as I update the data by filling in the empty spots. As basic need layers fill in, more advanced layers (advanced education, good environment, public transport etc ... ) could be added.

I would like to build a Ebd-to-End office management tool for small/mid size companies.

There are lot of tools available, but the features are diversified between them and don't have all the features in a single app.

My app would have employee management, attendance, accounts showing credit & debit, maintaining vochers and invoices, employee time tracking etc.....

This would be killer app if targeted for all small/mid companies...

Madan Narra