Ok first what is your budget
You wont find a 16 port wireless router
You will probolly have to get a good 4 port wireless router and pickup a 16 port switch.
Or you could have a router (cicso 827, 831, 837 or a cheap linksys befrsr11?) hook a switch dirrectly upto a router and use a wireless ascess point.
With 16's PC's your probolly doing something coroprate, and you need a router that will handle 16 PC's, your average router craps out at around 4.
And about speed, switches vs router will be the same speed (hey, more expensive 10/100 switches will be faster) and if you want, you can get gigabit switches and be SUPER fast.