I would care more about Facebook and Twitter if all my friends could easily tell that I was there long before any of them. The point is, I think early adopters take pride in being the first one in their social group to try something new, and they might invite their friends just so everyone would know they were first.
1) Your page assumes too much (it assumes I know about the product). It does not speak to me directly. EVERYBODY and their donkey makes plans, but who, what, how why will use you? For example, if this was for travel plans, I'd say "Taking the next trip, let us be your assistant (the value prop is not a place to write - a paper and pen can do that - it’s the benefits of having an assistant)."
2) That image makes it look difficult/techy product to use. You’re saying I will be using the tools NASA scientists use, that makes it not easy for me to do.
3) Your round logo makes you look old, not you age wise, but it makes your company look like something from the 80s. Like a soap bar logo. Look at the top 10 companies your customers like or use, and take hints from their logos. Honestly, I don't know why companies need a logo, just use a short form of your company name in its colors (hint: look at the top left corner of this page).
4) I said I wouldn’t pander but I can't help but say that your blog is awesome!
5) Inviting people to the launch party? That’s the benefit? But you’re not desirable enough (yet) for me to give up my email address for the opportunity to hang out with you.
6) For enticing people to sign up, I’d say do this: Give a solid value prop in your landing page so anyone who reads it wants it immediately! Then offer your service free for a limited time or something. This will do 2 things, first it will force you to sell your product/service in a sentence, second it will keep out people looking to get something free off you instead it will entice get people who are actually excited about using your service to try and get in - they will be your word-of-mouth army.
7) Add a descending counter (15 invites left) etc. to create a sense of urgency.
May you have great success!
remember that your potential new users have no idea who you are, and people are still generally suspicious of new things on the internet, and rightfully so.
Small items that are guaranteed might be a better bet. We are still testing this out. :)
We are at a conference right now and instead of an ipad we are trying out 40 $10 amazon gift cards.
Look for something that all users can get, such as thetrumanshow's suggestion of a "trendsetter badge", or something that a lot of people can get, such as "one out of every ten people to sign up will get a voucher to..."
Of course, this only works for a site that can let people in at a trickle.
Prior to the iPad, we've tested various types of giveaways to incent various actions and found that the best responses came from either big prizes or small, guaranteed prizes. YMMV.