I'm a huge fan of the Windows Phone Silverlight Toolkit.  Free  controls, with source code, and sample projects showing you how to use them. On November 2, 2010 the WP7 SLTK team released some new controls into the toolkit.  I thought I'd point them out for ya'll.

In order to get the new controls into your application, you'll need to re-download the toolkit, and recompile it into your applications. The November release of the toolkit may be found at http://silverlight.codeplex.com/releases/view/55034.

A quick overview of the NEW controls below.  Enjoy, and happy app writing!

AutoCompleteBox Very similar to the Ajax Toolkit's autocomplete box. Enter a 'clue' as to what you're looking for, and a filtered set of results will appear in an expansion panel over the control. Select the one you like, and off you go. The sample shows single and double line formats.

ListPicker
Comboboxes just aren't cool in WP7 dev. So use the ListPicker instead. Two formats available. The first expands in place to give you options. Useful for short lists. The second takes you over to another page witha full listbox to choose from then returns to the calling screen. You can see this in use on WP7 when you change Settings / Ringtones & Sounds.

LongListSelector
The People hub in wp7 uses a 'click a letter to get a selector that moves you someplace in a long list' type effect. Hard to do before the toolkit update, but not any more. Setup your catagories, tap main selector, get a categories list, then get returned into the appropriate place in the main list.

PageTransitions
Not for the mere mortal to attempt on their own, now a full suite of PageTransitions are available to you. Included are Roll, Rotate, Slide, Swivel, and Turnstile, along with various transition modes. In some of these talks attendees have reckoned transitions being akin to the html blink tag. Use with discretion, but here they are.