I have the 7200, 3200 and 1800 Icon Pro bags.
1800 = day hikes, day hunts, I carry this bag inside my 7200 and convert on backcountry hunts
3200 = weekend scouting trips, day pack in late season if I need to carry more clothing. It's larger than I would want as a typical day pack but if you can only get one you probably want this size.
A 30% off sale on all packs happened last week. Another 30% off sale starts 11/18 and runs for four days.