Here are some ideas and photos that might help you design and build your outdoor kitchen.
Slab Granite
Plus:
Easy to clean and look after; no seams; lasts long; looks great
Minus:
Expensive and difficult to install DIY (though possible, look for pre-finished slab granite counters made for kitchen use).
Granite Tile
Plus:
Looks great; less expensive than slab granite and easier to install -- particularly DIY
Minus:
Keeping the joints and grout clean; bull nose pieces and be expensive
Ceramic Tile
Plus:
Can be less expensive, and look great. Wide range of choices.
Minus:
Keeping the joints and grout clean
Professional Poured Concrete
Plus:
Limitless range of designs and colors; can look great; can be sealed for easy clean-up -- no seams
Minus:
Cost; can be as much as slab granite
Poured Concrete -- On-site or DIY
Plus:
Lots of control over color, shape and style; lower cost
Minus:
Can be difficult to get it right; can look rustic