Check-in times can vary between airlines. Here in the UK, for example, the same airport might offer a 40 minute check-in facility for certain airlines while it's more usually 2 hours (or 3 hours for transatlantic flights) for other airlines. Check with the relevant airline to find their minimum check-in time at Zurich.
Also check with the airline(s) to see if you've a through travel arrangement (where your bags are automatically transferred between flights) or 'point to point' flights (where you have to collect your baggage from the first flight and check it in for the second flight). If the latter applies there are left luggage facilities at Zurich airport:
http://www.zurich-airport.com/dokumente/?ID_si te=1&sp=en&doku=ZRH_Gepaeckaufbewahrung_EN.pdf &dtit=Left+Luggage+Office+%26+Lockers%3A+price +list
Trains run to the city centre every 10 minutes at peak times. The journey time is 10 minutes.
This map might help you get your bearings at the airport:
http://www.zurich-airport.com/dokumente/zrh_et agenplan_EN.pdf
For further airport information, start here:
http://www.zurich-airport.com/ZRH/default.asp? ID_site=1&sp=en&hp=1
For what to see in Zurich, check out the city's official tourism website:
http://www.zuerich.com/en.cfm/zurich/
Can$100 should let you get to the city and back, buy you a decent meal and a guide book and still leave you with a little change.