What colours do you tend to wear most?
Personally, I'd go with the tan, as I wear a lot of black clothes (with some brown) and I prefer black bags if they have other colours (or metallics) mixed in. I know the Paddy has the lock, but I'm not sure that that breaks the black up quite enough for me and currently, I feel that an all-black bag looks a little too 'heavy' on an all-black background.
But, if you tend to wear other neutrals (grey, tan, or brown) more, or bright, or very pale colours (pale pink, for example); a black Paddy would look lovely with them. It would also look gorgeous, worn in the French way, against navy.
I really wouldn't worry about repeating colours, or types of bag, as long as they are colours and types of bag that you love and that work for you. I don't think a bag, that you carry often, will necessarily be made obsolete by another style in a similar colour, as you will probably find yourself alternating between the two every week, or two.
At the end of the day, you know yourself best. I'm sure some people don't understand my bag choices, but they work for me!