Hmm, well I'm a bit biased... I have a pet tarantula, so I like spiders. And, as odin said, they eat other more annoying (and dangerous) bugs like mosquitos, etc.
Oh, and yes, the average person inhales/swallows a number of spiders/ other small insects evey year, not sure the exact number, but around 8-10 per year, IIRC.
(Just had to add that, a Tarantula 'smilie' from my other favorite forum, tarantulas.us)
