Keep
This is something to treasure forever (well you hope). For my sister i have a lovely ring which i hope she'll love. Of course the type of present depends on the person your buying for. Recently the Keep present for my friend was a mix CD of our favorite songs.
Something to use, in this case a pair of leopard print tights. In the past it might have been glasses, gift voucher, book, beauty stuff, and finally...
Something completely disposable such as flowers. This is often the most fun to buy because it can be a joke present or chocolates whatever.