Still, I was interested in trying to use the other pieces of the Office suite, particularly to see if they would not be such memory leaking RAM hogs as Office 2004. I re-installed Office 2008 to give it a whirl.
The thing I like about it is that Entourage does not seem to have the same memory leak problem in 2008 as in 2004. I suspected that running natively on Intel chips might make it better and it appears to have done so. If I run Entourage 2008, I don't have to quit it by the afternoon to free up memory. Word and the others don't seem to leak, but they hog the RAM from the get go.
Using both or either is not a big problem. I can still run Entourage 2004 when I get tired of looking at the horrible purple colors with Entourage 2008. I suspect this is because we use an Exchange server so it creates an identity for each. If you did not do this, I have heard of problems trying to share the same identity.
I don't like the fact that I can't select which version is the default to open a file when double-clicked. It defaults to Office 2008. Not a problem with Word or PowerPoint, but the opposite of what I want with Excel. I could trash Excel 2008 or uninstall all of Office 2008 and reinstall only Entourage, Word and PowerPoint. When I get a second, I will try that and post results.
Bottom line is that you can run them both. I will use them a little longer and give my thoughts on whether it is even worth it. I suspect I will conclude that it isn't worth the cost, but who knows?