I might be early for this year (rather than late for last year :haha: ), but in our house growing up, Santa always had either some biscuits and a Guinness/beer, or biscuits and milk (when the whole Drink/drive thing started - us kids didn't want Santa stopped by the police!!). And always a carrot for Rudolph (but that was always in the sitting room too - so he must have come down the chimney to leave big bite marks on it!).
Nowadays, Santa gets a mince pie or some cookies, and a glass of milk (although I may also push for a bottle of cola or fizzy orange this year instead). We also leave out soem veggies for the reindeer, but may make some magic reindeer food instead. (And apparently, as DD loves them so much, Santa wanted rice cakes last year - which would be good for his waistline but his helpers are not so fond of them in our house!!).