As far back as I can remember, the first update I got with VST support was from Pro Audio 9 to Cakewalk Home Studio XL, which worked for Windows 2000 and Windows XP. It had problems in Windows 7. DXi was more common, and you had to render the VST to an audio track so that Cakewalk would accept it in an output file. I remember it being quite heavy on my Pentium 4 at the time. :P