Matt, have you tried One Bus Away ( http://onebusaway.org )? It also provides public transit schedules for the Seattle area, including Sounder, and it does have real time updates for Metro, some ST, and Pierce Transit buses (dunno about Sounder).
For example, here are the arrivals for the next half-hour at King Street station: http://onebusaway.org/where/standard/stop.action?id=40_S_KS
(I guess there aren't any as I write this.)
I believe it also has its own Android app as well.
One of the first things I do to start my daily train commute is visit the Android Market on my new Sprint HTC EVO 4G. This morning I was very pleased to see that Google Maps version 4.3 was available as a free update. This latest version provides you with the latest information on restaurants, upcoming bus, train, subway, and ferry schedules, and the ability to find friends and family in Latitude.
I was most interested in the public transit schedule support since I find myself visiting the Sound Transit page if I need to jump on a different train due to a change in my schedule and that happens about once a week. Unfortunately, my Sounder train schedules are not yet in Google Maps. However, there are a ton of bus and even Washington State ferry schedules in there so it is still a very helpful layer to enable. The ability to view when the next bus or ferry will be available is extremely helpful and much better than just having a list of departure times. I wonder if the times change dynamically as real-time data is sent from buses, trains, and ferries?
The quick feedback on restaurants may also come in handy for those times you are visiting a new city or want to try someplace else to eat. You can also now share your location with people from your Google Contacts list and quickly send them a sharing request or drop them from the suggested friends list.
Google Maps on the Android platform is one reason I am a fan of these devices with the superb Gmail support being another key factor.
