You don't have Reese's over there? Then definitely a must add!
Skittles and Starbursts are a must too. I like Nerds as well and Gobstoppers.
I notice you're in Manchester - Mr Simms Olde Sweet Shop in St Anns Square has some American sweets and chocolate etc. Worth a look there to compare against eBay (especially as a lot of what's on ebay is probably bulk buying).
Warning - if you have a sweet tooth like me you'll want to buy the whole shop, it's awesome!