Hi there!
I just bought my shop last October. It came with a house, which I thought was nice

Seriously, though, the house is 1600ft. on the first floor, with a geothermal system. The house was built in 1990 and the geo unit is original to the house. The upstairs is 900 ft, and was added later (the house was built intending to have a second floor but it was unfinished when the previous owners bought it). So, upstairs has a smaller traditional heat pump.
Unfortunately the 23-year old geo unit was on its last legs when I bought my house, so as I write this, the local HVAC installer is putting the finishing touches on my new geothermal system. We didn't have to drill any new wells, since the house already had existing loops we could use, but everything else is being replaced. I'm told there are three loops, but I don't know for sure. My installer told me today that they usually drill 150' deep wells, one per ton. This is in Paris, KY (about 15 miles northeast of Lexington, KY).
For my installation, which includes about $1000 in replacing ductwork, and also including an electronic air cleaner and a built-in humidifier, is $17,700. The unit I'm getting is a ClimateMaster Tranquility TE30. Rating is 29.6 EER, 4.8 COP. I'd guess the air cleaner and humidifier are about $1000 combined. I don't have a breakdown handy or I'd give better numbers.
I'll qualify for the 30% tax break on most of that (not the ductwork, but certainly the heat pump itself) so that helps the price.
Given the initial cost, I thought about going with a traditional heat pump instead. They work okay in Kentucky (I grew up in a house with a heat pump, and my last house's heat pump worked fine for me for 14 years). I do not have natural gas on the property, so fuel heat for me would have to be a propane tank.
When I put my old house on the market in August (2013), the heat pump died pretty much the same day I listed it

. Replacing that heat pump with the cheapest Trane I could get for the house (1400 ft) was $5600 for both inside air handler and outside unit. For my new house I'd need a bigger unit. After the tax break I'm into my geo unit for around $12,700. I'm not sure how fast it will pay back, since I don't know how much it would cost to run this house on a traditional heat pump, but my smaller house's electric bill was averaging $150/month on cheaper electricity (Kentucky Utilities versus a co-op, about $0.025/KWh differnce).