It depends what kinda of spider or snake it is, I would say snakes are more dangerous though because many are venomous and some can like choke you. But if I had to pick to be in a room full of snakes or spiders I would pick snakes because spiders creep me out. Also there are some spiders that can kill you very quick, but I still think snakes are more dangerous. Also I would try to sing to the snakes or play my clarinet or hypnotize them. XD
Snakes are probably more deadly, but people fear spiders even more, because spiders are small, but can be very deadly. Also, your way more likely to come across a spider in your house, then a snake. As long as you don't find a black mamba in your house, you'll be ok snake wise, but spiders will always be around you.