I have big fingers so I bought a multipack of cheap rubber-tipped ones from ebay - they're aluminium with a soft tip that works on all types of screens.
But I found the ones from pound shops just as good as say a Genius Touch Pen. No complaints about the Genius, but it seems to work best with a larger screen or a tablet. The cheapies are perhaps best for a smaller screen. But these things are so cheap you can easily buy more than one type and see which type you think is best
