I've currently got an iPhone 3G and will be upgrading this Summer. I don't think I'm going to get another iPhone so I'd like to know if you all have any recommendations for a smartphone that works with Yahoo Mail and (preferrably) Push notification. I currently enjoy this feature on the iPhone and it works really well but I've only found RIM Blackberry offering this too.

I was looking at Android but am not quite sold on it b/c it's such a new platform. Windows 7 phone looks awesome. Any suggestions?

I'd love something that will sync with my yahoo calendar and mail. Verizon or AT&T preferable but not critical.