I'm in favour of pruning the announcements to the absolute bare minimum for 99% of the time, so that the occasional well judged humour really stands out.
My daily commute comprises three journeys: EMT Meridian NOT-STP, EC 225 KGX-GRA, and EMT 15x GRA-NOT. The variety of the announcements is vast.
The EMT Meridian & HST staff give long and verbose announcements about everything and anything. First prize to "Radio" Anne Bayliss she just never shuts up. The EC staff are more succinct, though recently have started to read out the ticket regs. The EMT 15x staff stick to the bare minimum of telling you where the train is going and where you are now.
Less of:
Where the saftey notices are (no one cares). Which coach is the First Class or Quiet Coach (you'll be thrown out of the former, if you are the noisy sort I guarantee you're also the type that doesn't pay attention to announcements).
Station stops, "The next stop is Leicester" is just fine, it doesn't matter if techincally the next station on the line is actually Sileby - we don't stop there. Or if the next stop is for the junction - the doors won't be released so we can't get off.
Padding words, "Ladies & Gentlemen, this Beeston, after Beeston this train will go forward to East Midlands Parkway." You don't need the Ladies & Gentlemen (the chime alerts us to the announcement) and trains don't go backwards, so why tell us its going forwards - anyway it depends which way my seat is facing...
More of (but only very rarely):
Please take your children with you - I don't like them any more than you.
Check you've got all your belongings with you, the paperwork to get them out of lost property is just awful.
This train is now non-stop for London St Pancras, which may be a bit of a surprise for the people on the platforms at Market Harborough, Kettering, Wellingborough, and Luton.
We have no idea when the line-side fire will be put out, as we're stopped at Peterborough I'm going to release the doors so you can have a walk. Please hurry back when called.
Your lifejacket has a light which illuminates automatically on contact with water and a whistle for attracting the sharks. (Lufhansa 1998 - everyone else was reading their newspaper, I nearly hurt myself laughing).