I scrapped the OEM horns. One of them had packed up and the poor thing sounded so anemic...
Mounted a set of Fiamm Freeway Blasters (one high, one low tone). I'm very, very happy with these, having put a set on my last two motorcycles and knowing that they're both loud and durable.
They're mounted a bit higher than the stock location (farther from water has to be a good thing). I angled them so that the opening is tilted away from the front to minimize rain intrusion and downward, to facilitate drainage.