Any of the names Beenthere mentioned but I am not a big fan of Lennox sister lines ( Armstrong and AireFlo/Ducane). Nothing wrong with them but you get a LOT more adjustment features on the higher end Lennox Signature series than the basic units of them and all the other brands. If you want a 2 stage system you really should get a higher end furnace/airhandler with a true ECM variable speed blower in order to get the full use/features of a 2 stage AC. Hence the more features/dip switch adjustments for fan cfm etc on the higher end units. Nothing is cheap when you are looking at those units. Basic price for an XC16 2 stage and G61V furnace here would be $10,000 and up to $14,000 with the full blown IAQ indoor air quality communicating programmable thermostats etc.
"Cut it twice and it is still too short".