> So far im looking at ....
> os 3.5 (its cheap)
It may be cheap, but 3.9 is at most $40-$45 US, and includes lots of bugfixes and extras. 3.9 was not as compelling when it was released, but with the BoingBag 1+2 updates, I wouldn't settle for less today.
> os 3.9
I'm using 3.9 with BoingBag 1+2.
> Directory Opus Magellan II + Magnum Opus
I never got on the Direcory Opus 5/Magellan bandwagon, preferring to stick with Opus 4, which is open source and updated regularly. As you've apparently also managed to get by without it, I'd suggest holding off for now, since the new OS should keep you busy for a while. I will consider buying Opus for OS4/PPC when it becomes available.
> scalOS
I tried it a number of years ago, and it always seemed buggy and unsatisfying. Maybe it's improved, but don't get your hopes up.
> (morphOS on a classic amiga?)
Uh-uh.
Hope that helps,
Todd