I use the by-the-book method plus the DMG-variant fumbles. The actual fumble description are completely off the top of my head, but the guideline is that the PC is effectively staggered (partial/standard action only next round) or his turn ends now or he loses his weapon.
Examples include getting a weapon stuck in an object, take a move-equiv to withdraw it (effectively only allowing a standard action next round); dropped weapon; off-balance, attack cycle ends; bolt shaft broke, take a move to clear the debris; and "you forgot to fully string your bow".
Since chucking your weapon is a fumble option, I allow a locked gauntlet to reduce the odds of a melee weapon fumble by 1, and it guarantees that you don't send your +3 sword skittering across the battlefield. No one has come up with a way to reduce missle weapon fumbles, yet, although I'm open to ideas.
Fumbles really don't seem to come up that incredibly often, so I don't mind them. If they became a problem, I'd likely adjust the system a bit.