I think cigars are social, while pipes are contemplative.
Cigars and golf, cigars and nightclubs, a cigar on the beach or on an after dinner promenade.
A pipe and a book, a pipe before bed or with morning coffee, a pipe while typing on the interwebs.
And per another thread on this board, pipes should be sipped slowly, while cigar are meant to create billowing clouds of smoke.
That's my two cents.