I personally prefer a good quality brandy - or even whisky – but nothing over 12 years old! I know that if you have a cold you can't really taste anything, but you may as well give you body a much deserved treat. And if you're going to go to the effort of giving your body a treat, you should not be using tap water! just think about all the impurities in it - and this is supposed to make you better?
Of course, you could just do without the tap water, the honey and just drink the good-quality brandy (or whisky) – no point diluting it :)