What is the best home improvement you have made?

That reminds me of one major improvement that I made but forgot- upgrading the attic insulation from 6" to 12". I don't know how much this is saving in energy costs but the house is definitely more snug.
 
1. Tarmac ... now we can drive all the way around the house, good for kids bikes/cars/skates ... and less grass to mow.
2. Pure wool carpets. Put down 5 years ago and still look like new.
3. Bespoke shelving unit in the study ... for Mr. HPs collections of dvds/books/magazines and other junk.
4. A large wind up double washing line 120ft long in the garden.

For 2006 I intend ridding myself of some more of the lawn and replacing it with shrubbery/trees/vegetable plot.
 
gas central heating. went from economy 7 electric heating with only 3 heaters in the entire house and a shower that worked no better than standing under a barely flowing lukewarm tap to lovely toastie goodness in the entire ouse and a fabulously powerful shower with unlimited instant hot water
 
In no particular order

Outside tap, wall mounted hose pipe & reel
Converted to Gas Central Heating
Gas cooker
Combi-Boiler, removed hot water tank
Replaced all the windows with double glazed units
Tiled floors in Hall, Kitchen, Dining Room
Folding stairs for attic
Removed built-in wardrobes in master b/room & created a walk-in-wardrobe (not huge, but much more effective)

Things I wouldn't bother with again
'Insinkerator' for chopping food waste
Solid wood kitchen doors - not worth the money
Wallpaper - anywhere, ever again
Carpet - anywhere, ever again


On wishlist
Storm porch for front door
Utility Room (but haven't worked out how!)
Convert attic
Re-do cobble locking/front garden to park two cars easily
Some way of storing/hiding the three wheelie bins in the back garden
 
"Some way of storing/hiding the three wheelie bins in the back garden"

At Claregalway castle garden festival last weekend and seen these purpose built wooden screens that doubled up as planter bases for either veg or flowers. Personally we've our bins inside shed and leave the lids open all the time so just matter popping waste in.

Best thing we ever did in five year old house: fit a stove into original fireplace, fantastic return on a mere €650.
 
New, younger husband

With pension

No-maintenance garden

No stairs (bungalow)

All wooden and tiled floors

No wallpaper

Big shed for loadsa stuff

Mobile broadband (Bye, Bye Eircom)

Freeview TV (Bye, Bye SKY)

Only wish there was piped gas here, have to get rid of oil burner