The good news is that we should have our new furnace installed tomorrow. Just in time. Our house holds the heat pretty well (one of the few things our builder did right). So, even though temperatures have been near 50 at night and only in the mid 70s during the day, we haven't had to run the heat yet this year. Also, the contractor asked for a hefty down payment, which had me worried.
The problem with having good appliances to begin with is there's not much you can update to. When we did the water heater, we did see a good change (in both hot water available and in gas usage). But with the furnace we're going from 92.5AFUE to 95.5AFUE, not much difference. Our current furnace has a single speed blower and the new one has a four speed, so we might see some difference in the electrical usage. The new furnace also moves 25% more air, which also should help. I did look at getting a DC motor (significantly less electrical usage), but the cost for the upgrade was too high for the budget; so was a two stage burner (savings in gas). Just like the hot water heater, I could have upgraded to a greater extent, but the cost of those upgrades were too high.
With the dishwasher it's still too soon to notice a difference (except for sound, man this one is quiet compared to the old one). Although energy and water usage and where part of our criteria. I don't think the one we got was the most energy efficient (although it was close), but it should use less water overall, which will help us.
When I build my own home from my specs, I will go to these better options (tankless water heater, insulating the hot water pipes all the way from heater to outlet, and a multiple stage burner, DC motor-variable speed blower, high efficiency furnace).
Next up in the appliance wars is the washer and dryer. Currently the washer isn't draining as fast as it needs to, so it's not spinning enough. I've checked those things I can check and I've not been able to see anything wrong. My guess is the "self-cleaning filter" isn't so much anymore, and I'll try a higher and longer dose of CLR to help (from what I saw it did help the first time). I can also replace all the hoses (which I probably need to do anyway). While our washer/dryer combination isn't the most efficient (they were gifts, just like the AC), and we could probably upgrade a little, the best efficiency products are a little out of budget (unless I start getting OT like last year again). While a top loader washer can run between $200-600, the front loaders start at $800 (for a brand I don't trust). Also, while looking at washer/dryers while shopping for the dishwasher, most front loaders weren't rated for energy usage (or the sales people took off the tags). So this will probably have to wait until mid next year. I'd also like to upgrade the AC, should have done it with the furnace, but just didn't have the cash. We were also looking at installing a wood burner this year, and that won't happen.
On the "I have a dream" board is adding skylights and extending the house. The furnace will handle what we're thinking of. But without a loan or major OT increases, probably several years down the line.