I’m sure the other more experienced folks here will have more
useful/extensive for you but I’ll offer my advice. Not
sure what specifically you’re looking for, but you could try:
http://www.lacywest.com/ for general jewellery tools and such, they
seem to have a good variety
http://www.theringlord.com/ is geared towards the chainmail crowd,
but they sell silver, goldfill, some gold, and niobium wire at good
prices, they even have some casting grain (sterling). They also
carry some beads, findings and clasps. They’re super handy if you
want pre-made jump rings.
http://www.imperialproducts.com/ sells a wide variety of
metals/alloys (gold / silver) though I’ve not done much shopping
Good luck in your search. I’ll be watching this thread too, for the
same reasons you asked.