oh. i see others have posted while i was image-hunting, and we've all said the same thing. candles and chocolates!
and yes cut flowers or a houseplant are always a good fall back but like Bizi says, if time comes and you haven't found anything, take the pressure off and just show up.
if you want to do a plant, i recommend a
bromeliad already in bloom. they are sturdy and do well as houseplants. their flowers last a LOOONG time, so even if they die, they will "outperform" cut flowers and you'd probably spend less than on a professional floral arrangement.
~ waves ~