I tend to gravitate to 5 hi-caps for the guns that take them, plus 4 or 5 10-rounders. Lower-capacity guns, about 5 each, except for the really small ones. (Why do mags for pocket guns like the Beretta Tomcat and the Kahr MK9 cost so damn much?)
Some of the hi-caps I've put away while brand new, for possible sales/trades later. I have about 9 hi-caps for the Beretta 92, because I got a great deal on some aftermarket ones (5 for $50) that have never failed once.
The hi-caps I use, I use at the range all the time though. I'm not going to pay all that money and not have a little fun with them. I don't drop them on the ground, though.
One of the main reasons I have a lot of mags is because I too like to load them at home rather than at the range, especially if it's very hot or cold outside.
By the way, Brownells carries these great nylon pouches with velcro closures for storing mags and bringing them to the range. They come in 4-, 6-, and 8-mag sizes (assuming double stack mags; they hold twice as many single stacks), in 140mm and 170mm lengths, and in lots of different colors. Pretty cheap, too, with the trade discount. I bought a bunch of them in different colors, and now I can just throw the ones I need into my range bag. It's also easier to keep track of specific mags, like the malfunctioning ones.
