This broadfork is what I use anytime I have a garden bed to prepare and want to loosen up the soil and add amendments before planting. Tillers are unwieldy, destroy soil structure and vital organisms and are generally unsuitable for raised beds. A standard pitch fork is fine but an ergonomic nightmare if you have a large area to work. The best solution I have found is the broadfork. It uses your body weight and two long handles for leverage and loosens a large swath.
I bought the Johnny’s 520 Broadfork from Johnny’s Seeds as it was large enough for my needs, although there are various sizes available. I use it regularly and the amount of soil it can turn with a modicum of effort is remarkable. I started using it this year and think that any serious vegetable gardener looking to avoid the roto-tiller would welcome this in the shed.
[Note: Johnny's 520 is temporarily back-ordered. You might also consider the U-Bar Digger from Lee Valley ($139), which has a slightly different design. -- OH]