Which Thames River Cruise from Westminster to Greenwich should we take?

MBNA Thames Clippers are the ones I always use, but they are a simple commuter service, no tourist commentary. There isn't a great deal too see / commentate on down river of Tower Bridge, so you might as well get to Greenwich without delay, and the MBNA Thames Clippers are great for that. An all day hop on / hop off travel card is around £15 I think. The services are regular, every 20mins, the boats are clean and warm (there is no outside seating as such, a little at the back is all) and there is a café on board. Seats are aircraft style with little fold down trays. They are run buy the Government (TFL) so are super safe and well run.

http://www.tfl.gov.uk/modes/river/about-river-bus

I don't know about tourist services, but the one time I did a tourist trip, it was a ticket bundled with a London Eye ticket someone bought me. The boat ran between Westminster Bridge and Tower Bridge and lasted about 45mins, and was really good as I remember. There are lots of tourist boats running between those two points where all the main stuff to see is.

Thank you MIke J for the information and the link. We are excited as our trip approaches. Can't wait to explore.

Greenwich is a nice day out, weather permitting. You have the 'Cutty Sark' right where you get off the boat. Close to there is a working local brewery, which you can tour. There is a nice pub with a restaurant in the same place, serving the beer they brew. You have all the naval college stuff to look at, and of course a walk up to the Observatory (a very steep walk, gets the heart going and the brow sweating). You could book tickets to the Planetarium also, which I'm told is a really good show. You can see the 'Meridian Line' without paying to go inside, and stand astride it, if you so wish (of course you have too!), on the public footpath just below and in front of the official Meridian Marker.

Stunning views of the Canary Wharf part of London. Worth jumping back on the boat, going one more stop down river to the O2, where you can walk over the top of the 'Millennium Dome' or get the Emirates Cable Car over the river. Only a 4 minute ride, one way, but actually worth it. You could then get the DLR back into London, or do a round trip, and get the boat back.

Worth getting off the boat at 'Bankside' and wandering around. Visit Borough Market which is there if you're into food. Even if not, Shakespeare's Globe is there, and lots of nice pubs, and restaurants, and the Tate, and St. Paul's isn't far... and... and... ok I have to stop now, I could go on all day :o)

All great information Mike J. I will definitely be set for a great day out. Now to hope for good weather. :)

Can't help with that sorry 😃

Here's a suggestion from Rick's book:
Take the boat to Greenwich for the scenery and commentary and take the Docklands Light Railway back.
Use either City Cruises or Thomas River Services for the trip to Greenwich.

It's not the only way to do it, but the best in my opinion.