caldera? Do you mean Cedega
Most hardware (all but "bleeding edge" stuff) is supported by most major distros out of the box. Your DSL modem should work fine, depending on your distro.
Windows games will *not* run; some will run under Wine/Cedega, some have native linux versions, but mainly, they won't run.
Photoshop will run in Wine, but there are good open-source alternatives to most Windows programs. Check out the Gimp for a photoshop-like app.