Yeah, it's easy to pick and choose what software goes in. You can just re-install the missing bits over the top using an install disk for the same version, or you could grab a copy of Adobe Premiere 4 or something and play with that.
7.5 is nice enough, on a 7600 I'd sooner install 7.6.1 because it feels more stable (probably personal preference), but with 200MB RAM, I'd probably just run 8.6.
Keep in mind that USB doesn't work in 7.5.
The best solution though is always to install several different OSes on different disks or on different partitions
I generally tend to partition my disks into multiple parts and put a few different OS versions so I can switch between them depending on what I want. My 8600 has like, 7.6.1, 8.6 and 9.1 on it, or something like that.