Let's see, Street Fighter IV, Valkyria Chronicles, Persona 4 and those were ages a go. Recently on the PSN I've bought Worms, Zuma, Fat Princess, Final Fantasy VII.
 
They're cheaper, proven quality and I don't have to leave the house to get them. But I can see myself getting Arkham Asylum, Tekken 6, FIFA 10, Dragon Age: Origins on disc whereas the only downloadable left that I really want is Trine so maybe it's just a case of timing.