If you like silver and wanted something a little different looking in your tank you could always try and go for Hatchetfish. I have seen them in silver and marbled. They grow to be about 2-2.5" long and are a schooling fish. I have some in one of my tanks & think they make a very nice addition. If you would like a pic and additional info Click Here.
Thanks for the replies - the Rasbora's are a very interesting option! I think I'm going to have to think long and hard about what to go for - you guys have certainly provided some ideas - many thanks.