vegas pro /dvd architect version confusion

Hi..am a little confused as to the different versions of Pro 8.0 and dvd architect 4.5. I logged on to the sony website recently looking for info and it seems they have quite a few updates, however am not sure what specifically i need. I run a 2.4ghz quad core,xp pro, 2gb ram,with 512mb video card. Am curious if anyone would be able to tell me which updates would really be of use to me.I would to like be up to date without installing anything not necessary. Am beginning to do more for public access tv and am considering a purchase in the near future of a canon hf10.I would like to make my experience as painless as possible, and would appreciate any advice anyone would be willing to share. I currently have Vegas Pro 6 and Pro 8.0a installed as well as DVD Architect 3.0 and 4.5...Thanks in advance and Aloha