Most announcements are mandatory (FAA or company SOP) so you don't have a lot of choice on those. As a commuter, I like to hear these "extra" flight deck announcements (and that is what I do)...

- If delayed during taxi, ET to T/O
- Enroute landmarks (and revised ETA) only for significant landmarks on long flights (daytime only, at night please ****)
- Descent announcement w/ ETA and gate. At night I delay this as long as possible.
- Reason and ETA for any post-landing ground delays.

The announcement to stay seated while waiting for marshallers is actually a very good idea...otherwise all the paxs get up and open bins which can create a problem when you finally do pull forward and hit the brakes. It saves the FA the trouble of yelling at people.