My personal one is very small due being on-grid and knowing it's cheaper to go the route of conservation that RE.
Beyond that I've set up standy systems that include diesel gen-sets in the Kw size, MGE UPS systems that have 4 banks 12V batteries with a DC output of 480V plus a few home sites with anything from 100watts lighting for a deck to two 300watt solar panel systems, one which was an upgrade from an old HF 45watt system.
Plus some units over in Philippines along with their designer < and fellow forum member Rich H.
Next on my list is a small 600 watt system restore system in Papa New Guinea.
Why do you ask?
Oh just curious.
I went out and purchased a "kill A Watt" meter... Here is what I want to power on my second floor.
1. 110g: 2 Medium Sized Canister Filters, 1 250w Heater and a 48" 4 bulb T5 Fixture
2. 60G: 2 Aquaclear 70 HOB- Filters, 300w Heater (yeah I should switch this one out with the 250w in the 110g) and a 48" 2 bulb T5 fixture
3. 40g: 2 Aquaclear 70 HOB- Filters, 200w Heater, Single Bulb 24" CFL Fixture
4. 15g: Aquaclear 70 HOB- Filter, Single CFL Fixture
5. 10g: Small HOB Filter, 50w Heater
6. 10g: Powerhead filter w/ Sponge filter and 50w heater
7. 3 5-tank air pumps on a Manifold to power the 7 Box filters and 3 Egg Tumbler Air Stones.
I tested the wattage with the K-A-W meter by turning all of the lights on and the heaters slightly up.
Take a wild guess at how much wattage I'm pulling all together with the heaters and lights on?