Perhaps a bit late crowsashes, but I love this website for unusual presents:
http://www.steptoesantiques.co.uk
In fact, I am thinking of doing something similar myself, as I am addicted to antiques auctions.
I know 'antiques' sounds expensive, but there are some cheaper and some expensive ones and some pieces are lovely. I think it is nice to give a present that has been around for tens or a hundred years, with all that history attached to it. For example I bought some 1920's seed packets (gorgeous colours and flowers on the cover) and had them framed for a gardener friend of mine as a present. Was quite gutted to part with them actually!
Hope whatever you choose is appreciated, but don't beat yourself up for buying vouchers. As was said before, at least you can choose the shop. I have a work colleague who is basically sponsored by Next and Marks and Spencer, and when I bought her a bunch of sweet peas (from my garden) on her b'day and left them on her desk, she was completely disinterested...you can't please them all.