We are the best!
From one perspective, you want your new startup to be the best - because, in a lot of ways, that is what will distinguish you from your competitors. The difference in market-share between Google and Yahoo! is an obvious example. So is the difference between Amazon and... whoever comes second after Amazon.
Clearly it pays big to be the best in your niche. You need to be the best. "Good enough" not only won't cut it, but will relegate you as indistinguishable from the swamp of mediocrity in which all the other companies float.
In this sense, "good enough" is the enemy of "best".
Good enough. Ship it!
And yet, you need to *ship*, because if you don't have anything to ship, then the customers will never hear of you. This follows from the principle of "ship early, ship often". It's all too easy to get caught in analysis paralysis, endlessly perfecting what you've got without ever putting it "out there" for real users to get their hands on.
In that respect, "best" is the enemy of "good enough".
So which is it?
As with everything, you need a strategic balance.
You don't need to be best at *everything*. You'll wear yourself out trying. You just need to be best at what you've chosen for your market differentiator. Perhaps you're aiming to provide the best features for power users, or most comprehensible features for beginners, or even the nicest customer service. Whatever you decide on, use that focus to drive your quest for perfection. You can push for the best in this one area and let other areas be "good enough".
If you try to swallow the elephant whole, you'll never get it down. Instead, keep focussed on your core competencies, and don't worry *too* much about perfection in the other areas. You can always make them better in your 2.0 release.