I won't be satisfied with anything less than Fusion power.
And no, I'm not holding out for Antimatter engines. They're more dangerous than anyone lets on, you know.
Oh, and antigravity propulsion would be nice, too.
No; no anti-matter. Nasty stuff.
Bethe solar cycle mass-energy converters are the way to go.
Shovel BS in at one end, and get all the electricity you could ever use out the other.
Works good for tracelessly disposing of inconvenient bodies, too.
Warms you three times...once when you cut a cord of wood; a second time when you burn it (for ambience) and a third time when the smoke & ashes were fed into the converter.