HTC 7 Mozart on Telstra, or HD7.
Both Windows Phone 7 devices... what an awesome operating system
Built-in Xbox live to boot
And free MS Office.
Astronomy apps aren't really supported though...if you like astronomy apps. I'm hoping this changes as the marketplace grows.. which by the way, is growing faster then the Apple App Store and Google App Store grew in their infancies
If you're not on Telstra, the Omnia 7 on Optus is probably the best WP7 phone out there. Just a shame it's not quad-band so doesn't support NextG.