[albee1952]

There really is no advantage to moving up to version 9 that I can see. A much wiser investment would be to build a newer system based on a new version of Pro Tools(regular, NOT M-Powered). Here are some reasons I suggest this:
1-newer computers and current Pro Tools are all 64 bit, which gives a serious boost in performance
2-M-Powered is somewhat limited in what interfaces you can use(regular PT now can use almost any hardware at all)
3-if your current setup works, by building a new system allows you to keep the current system in working form(and, your old hardware is likely old enough that its time to replace it anyway)
4-as painful as a big upgrade can be, the rewards are well worth it for the new features and performance of a 64 bit system.

so, to recap, I would either do nothing and keep making music with what you have, OR, set aside enough money to buy/build a new computer and new Pro Tools software. Your old interface may still work(but there are many current options that sound better than most of the older stuff). Keep in mind that all your 3rd party plugins will need to be updated to the modern AAX format(no more RTAS).