Keep on budget by using luxury material sparingly. Reserve the island for an expensive granite countertop, for example, while using more affordable materials elsewhere. Don't overlook butcher block and stainless steel.
If you find irregular surfaces at the glue line in wood projects, the problem can be moisture levels. This can happen, for example, when one piece has a 15% moisture content, while those next to it are at 8%. If you glue and plane boards with unequal moisture, those with higher moisture will eventually shrink more than those with less moisture.