I buy the various Thunderbirds vehicles (Thurderbird 1, Thunderbird 2, Thunderbird 3, Thunderbird 4, Thunderbird 5, The Mole and Lady Penelope's car FAB 1) on eBay. I like the diecast models, but I know other people who buy the plastic ones. I even bought a Tracy Island setup, it is my 5 year old's favourite toy!
My kids like the classic TV series figures, released by Carlton in the 1960s. But there is also a range of Thunderbirds toys which were released when the movie re-make was released in 2004 (there is no supermarionation so it lost a lot of it's attraction and they changed the shape of the vehicles a little).