From searching around, it seems that it's a good idea to have a small 1/8" drain hole in the bottom of my BB shell on my steel-framed bike. I've got the BB out to spray some FrameSaver, so I'll let the FrameSaver drip through the hole after I drill it. Once I've got everything back together, would folks suggest leaving the new drain hole open all the time, or perhaps plugging it with something like an earplug and removing that for draining liquids after a ride in the wet?
On a related note, the small vent holes in the chainstays and seatstays look like prime openings for water to drip in during wet rides. Should I bother trying to seal them with tape or something?