Hands down, one of the best small-space solutions for kitchens is the addition of a butcher-block island. We have one in our kitchen, and with it, we have a giant space for chopping, rolling out dough, plating big meals, and eating (it's become our primary dining space) plus storage for appliances, large pots, and hanging space for our dishtowels. It's kind of like a miracle.
I have seen so many people who are taking our Kitchen Cure struggle with their small spaces and if I had to recommend one piece, it's Ikea's GROLAND. Starved for counter space but blessed with an open-plan kitchen, we lugged this piece from Ikea up our four flights of stairs and spent a good hour or so putting it together. And it was worth it. It's supported a busy cooking life and abuse administered by a small child for the past few years.
At 21-inches by 47-inches, it runs the length of our small kitchen counter, offering a logical place to spin around, dump a hot pot, roll out a pie crust, or serve waiting guests a drink. It is solid wood and very sturdy provided you put it together properly. My one recommendation is that you use treat the wood with an oil like Bees Oil, or mineral oil. Bathe the wood before using it, then apply a thin layer with a rag once a month or so.
I see this piece in many kitchens, most recently in a Scott and Ray's Colorful 10-Year Renovation Kitchen Tour
Buy It: GROLAND Kitchen Island (at Ikea stores, $199)
Related: Best Butcher Blocks with Seating
(Above image from Scott and Ray's Colorful 10-Year Renovation Kitchen Tour, by Dana Velden)