This is the 2.5kW system I had installed in 2003, with 18 165W panels (2970W nameplate, but caps out at ~2500W due to latitude and angle).
Update 2016 - System required no maintenance until the inverter gave out in 2016 (13 years of operation), replacing the inverter and bringing the 220 interconnect up to current code (it needed a neutral wire) cost around $2500. System still producing 16+ kWh/day in summer.
I'm planning on upgrading the existing panels and expanding the system soon. The existing garage roof area today can fit ~5kW (nameplate) using modern panels and the main roof area on the left side of the house can fit another 5kW or so. Other spaces are available but probably not economical. Due to variable shading I may have to use micro-inverter panels on the main house instead of DC strings as I have on the garage. I'm reserving the roof area at the very top of the house for a future solar water heating system.