The appliances in your kitchen are going to be a very important investment. Quality is going to be more important than quantity here. Yes, it'd be fun to go crazy and get a rotisserie, warming drawer, AND a pizza oven — but do you really need it? Get what you'll actually use, and make sure that it works well, and is made for the outdoors.
This little outdoor kitchen has just the right essentials — nothing more, and nothing less. Make sure your appliances can plug into GFCI (ground fault circuit interrupter) outlets, and are Underwriters Laboratories approved.