The American ergonomist Chris Adams has written a review on a new type of stainless steel spade : http://ergonomics.about.com/od/gardeningequipment/fr/appel_spade.htm He has given this spade the maximum of five stars.
If you are at all into gardening, and ever have to dig or plant when the ground is a little 'damp', or you are lucky enough to have clay <g>, then I would urge you to seriously consider investing in stainless steel tools, especially your main digging spade. Having suffered over an inherited spade for some years, I was relieved when it finally went to the great potting shed in the sky, and I was able to indulge in some retail therapy at the garden centre. I ended up buying a Wilkinson Sword Stainless Steel Garden Spade, having played with everything the centre offered, I found it to be well balanced, and properly finished with no rough edges to raise blisters. I thought it worth paying that little bit more to purchase something strong that will probably outlast me. The joy of using it has been a revelation: being stainless, it stays clean better with little help from me, so I don't end up moving a 20kg mud lump on the end of the handle. Another advantage is the low maintenace aspect of stainless: although it is good practice to clean any mud off, it will not rust when put away damp, so it doesn't end up with a a pitted surface, even more prone to collecting mud! I've also found that I don't need to worry about keeping the edge sharp[ish] as it holds its shape very well, despite being abused and swung like an axe into tree roots because I was too lazy to walk to the shed for the real thing. This exercise also proved how well the handle is socketed into the blade! I would recommend a this spade to anyone, unless they have a problem back, or are not as tall as me, when I'd recommend the smaller 'border' or 'ladies' size. [Wilkinson do a full range of stainless tools- just add them to your christmas present wish list!]