It really depends on what tools you have available to you. Brake fluid is a pretty easy deal if you have a helper, spark plugs are easy but certainly not due yet (maybe shoot for 50K which is still early). Fuel filter isn't due and as far as the diff goes, yes, that's what he's refering to, but 30k seems quite early. I'd go for 50K as long as you drive it frequently and then do plugs, fuel filter, A/T fluid and if you're feeling saucey, diff fluid. Air filters and cabin filter though are pretty simple and are due if they haven't been replaced.