For travellers, what's changed since 2000?

There are a lot more accommodation types available now. Yes lot of new hotels but some closed over last 5 years. The B&Bs have improved a lot over the last few years. Great value in Hotels also outside peak season

All pubs and public indoor places and all work places are smoke free by law

What's changed since 2000? A lot! :-)

Cell phones are everywhere. Your current phone will probably work without having to do anything (but check on cost, it can be high).
The Euro is the currency in Ireland. (Of course still GB Pounds in Northern Ireland.)
Don't take Traveller's Checks. No one will accept them. Even banks don't like them.
Don't take currency to exchange. You will have to search a lot for a place to exchange them and the rate you get will not be favorable.
ATMs are everywhere, use your debit card to get cash at a good exchange rate.
Credit cards are popular. Still not universally accepted, especially in smaller shops and many pubs. Make sure the ones you take have a chip.

What has not changed is that the people in Ireland are some of the friendliest you will find anywhere in the world. They like talking with Americans and seem genuinely interested in hearing what you have to say.

AirBnb accommodations have become extremely popular world wide. Spent last November in the UK and used them exclusively.
Did your other trips to Ireland include adventures in Northern Ireland as well? If not this next trip should include NI. Imagine you'd all enjoy the Titanic Museum. The Giants Causeway is so unique it's sure to please everyone. On the West Coast of Eire try to hike, or take a trap ride into the Gap of Dunloe and don't miss visiting the stellar Killarney National Park. As far a pubs none of them hold a candle to Foxy Johns in Dingle.

The road network is vastly improved with motorways linking Dublin with Waterford, Cork, Limerick and Galway and improved road connections with Belfast.

If you are driving though, the Republic now has speed limits in kilometres per hour, NI still in miles

We spent 3 weeks in Ireland this past September and stayed in a number of wonderful Airbnb cottages. When using the site, you can use the filters to search for places with the number of bedrooms and the number of beds that you require as well as the amenities you want, like wireless, washer and dryer etc. Of course a sit down breakfast is not provided, but most of our hosts did stock a few basics--bread, milk etc. (and one even provided a gourmet kitchen, fully stocked fridge and a bottle of wine!) And really, shopping at the local Supervalu was interesting and fun.

As it happens, one of the places we stayed was Westport, and we enjoyed several wonderful evenings at Matt Molloy's! They had the best trad sessions we encountered during our whole trip.