Inspiration

Here's a compilation of web sites that compile beautiful user interfaces:

People Who Know What The Heck They're Talking About
http://worrydream.com -- This is Bret Victor's web site. Focus on his research topics.
http://www.uiparade.com -- Nice Photoshop aesthetic.
http://www.mnml.com -- Focused on ID more than UX, but great designers nevertheless.

iPhone Web Apps (HTML5)
http://cssiphone.com -- Great gallery presentations.

Aggregated Lists

Android
http://androidniceties.tumblr.com/
http://www.androiduipatterns.com/2011/12/how-should-android-apps-look-like_16.html#more

Apple iPad
http://stylishipadapps.tumblr.com/

User Interfaces (Web)*
http://dashboardspy.com/img/
http://www.dundas.com/dashboard/online-examples/
http://sortfolio.com

Tables (Web)
http://webexpedition18.com/articles/tables-in-web-design-beautiful-examples-and-best-practices/

*I'm not saying all of these are pretty, in fact quite the opposite for some. But it's more to get inspiration about applying dashboard-type functionality to a mobile tablet app