I would recommend lennox, carrier, or trane as quality name brands, however you basically get what you pay for.
The heating and cooling system does more for your home that any other appliance. Why spend thousands on new bathroom fixtures and then cheepen out on the furnace. I actually know people who spent $10,000 on bath fixtures and then wanted to cheepen out on HVAC.
Stay away from cheep stuff that starts with the letter "J" and think about air cleaners and humidifiers while your at it.
However, it all depends on where you live. You don't need as good of a system in Florida as you do in Wisconsin. LOL