This is a fair question, and one that many wrestle with whether they admit it or not. Some posters, as you have seen, simply relish in stupid ******** when someone asks a legit question.
For me personally, I have found that the absolute best product to make paint look brand new smooth and shiney is Moto Pro Spray Polish. This product is chemically the same, I am told, as Honda Polish. Moto Pro is available at Cycle Gear at around 5 bux a can (and worth it). You can use it on your paint, chrome surfaces, metalic surfaces, your helmet, and yes, your windshield and your helmet visor. You will be amazed as I was the first time I saw it work. It cleans off bugs and grime as it polishes. After you spray it on, the first couple of strokes with your cloth will clean the surface, then flip over the cloth and the last few strokes restore a showroom gloss. Go ahead to WalMart and buy a couple of packs of baby diapers for your buffing and shining. Not disposable diapers, but the cloth diapers. They are soft, washable, and work really well for a motorcycle.
OK, so there you go. This will fix your water spots. Have fun and ride safe. Joe