For a very stable, dependable ROM check out TKC. I have a 5500 and have been running it for a few months without ANY incident. Some of the functionality you are looking for will need to be added in via IPKG.
I've tried OZ/Opie and agree with padishah_emperor...it is a neat concept but unless you really are technical (not to mention patient) it would probably be too unstable for what you have stated. That is not to say it won't support the few applications you state, it merely means that you'll most likely have to spend more time getting them set just right.
I actually preferred OZ/Opie as I liked the "bleeding edge" attitude. However, I found that 90% of my use for the Z was as a PIM. So, I reverted to TKC for stability.
Good luck...and try them all out. That ultimately is the beauty of the Z. You're not locked into any one approach.
