Here is the house that my lovely wife, Katherine, and I own. Or vice versa. Some improvements we've made:
Painted every paint-bearing wall in the house
(from dark olive in most cases to off-white)
Painted every ceiling white
Pulled up dark olive carpet from first-floor
hardwood
Refinished hardwood floors on first floor
($1100)
Installed new hot-water heater ($200)
Installed new boiler ($3000)
Took out the bushes (free)
Installed new windows ($6500)
Installed new thermostat upstairs ($126)
We've sunk a shitload of money into the house, and we've had it for a year-and-a-half.