You hear it every day by VCs, entrepreneurs, and strategists... "It's not about the idea... it's about the execution of it."
Entrepreneurs who still need to learn this lesson should look no farther than this post from Paul Graham called "Startup Ideas We'd Like to Fund."
In this post, Paul lists 30 ideas (more like concepts) which need to have real businesses behind them. "30 free business ideas from Paul Graham?!" you may ask, wondering if he's gone crazy, giving away such valuable information.
But the ideas are not the point, it's how and whether or not you execute on them.
For example, the following bullets (click through to read Paul's details on each) are ideas which I've had detailed and explicit business ideas for:
3. New news.
7. Something your company needs that doesn't exist.
12. Fix advertising.
17. New payment methods.
23. More open alternatives to Wikipedia.
29. Easy site builders for specific markets.
30. Startups for startups.
So, of course these are problems, and of course I would have had specific and plausible ideas for how to address each one of them; however, that's not the point. The point is what I or you or anyone else ends up doing.
The real signs of an entrepreneur, therefore, is someone who does. You don't have to do right, but you have to do -- and your fabulous idea... well, that's not enough.