I think I go the other direction from many of you. Barring some really bad/corrupted hubs and/or super cheap heavy rims/tires, I don't see that much difference between cheap-ish (but well adjusted and maintained) wheels, and expensive wheels --beyond simple weight differences. Friction losses shouldn't be that different. And if you don't race, I would consider super expensive feather weight wheels to be a big waste of money. If you are touring or doing casual riding, then durable and comfortable is way more important than super race worthy. I'd get supple casing, larger tires and then service the hub bearings and races so they are very smooth. (Again, --unless your current wheels are really terrible junk)