Yeah, your bike sounds pretty good. I've got a 50/36/24 chainrings mated with a 12-26 (9-speed) cassette. I've not touched my small chainring since putting this together. On today's hilly 30-mile ride, the lowest gear I touched was the 36-21. I've got gearing for sustained mountain climbs, but I live in a rolling area.
You note that you only add a few useful gears, but I suspect you'll enjoy having more closely-spaced, easily-accessible gears for the exact grade you're on, or headwind you happen to face at the time.
(That said, I just built up a fixed-gear bike...)