Had no idea Dual was a secret DIY master. Dual It Yourself.
I do bits and pieces but rarely 'from scratch' stuff - usually limited to putting up shelves, building furniture etc. I would very much like to learn some proper skills such as plastering.
One request to the OP - could this be a gardening thread, too, or is that a bit of a stretch?
In addition to Dual's list, my best tool purchase was a cheap electric screwdriver and a set of heads, including hex/torx adapters. I use it all the sodding time. Can't imagine having to put furniture up without it now.
My best achievement was probably putting up these shoe shelves for the other half. I scored massive boyfriend points that day.
I have also floored a couple of lofts, which is no fun:
Created a vegetable plot in the garden (this pic taken before the lawn was turfed):