Digital BW, The Print

I was wondering if anyone is running BOTH, Photoshop 6 & 7 on their machine.

I'm not sure I want/need 7 as I'm pretty comfortable with 6.  Not real
knowledgable about the differences (asking for enlightenment here ;-).  Now,
moving from 5 to 6 was very much worth it for me with the palates being able
to be tucked away, text especially...oh, and the layers effects - those were
all good reasons for me to move from 5 to 6.

Plus I'm curious if you can run 6 & 7 on the same machine, setting one in
particular as the default.  Reason this occurs to me is when I went from 4
to 5 immediately with an upgrade they were both on the system, and
accessible as individuals.

Thanks,
Cleavis