Can I use a shop-vac for dust collection in a workshop?
Yep. You can use shop vacs for this (albeit you might need some adapter hoses). A neat thing to get is a power switch that can switch on another appliance one the first is turned on. The idea is you plug your saw and your shopvac into it, and when you power on the saw, the shopvac powers on at the same time:

http://www.amazon.com/Smart-Strip-SCG5-Autoswitching-Technology/dp/B000L9FQUO