1) How viable is Amiga os4.1 to use as a main machine?
Depends on what you're willing to give up from your current computing environment.
2) I read somewhere that Firefox is available for Amiga os4.1, is this correct?
Nope.
3) Does this handle flash as well?
Nope.
One thing I am not 100% sure on. I use Dreamweaver and Photoshop using Wine in Ubuntu. Is there anything similar in Amiga OS4.1 that allows you to accasionally run a Windows app.
Nope.
Finally what sort of hardware is required, to get back in to Amiga.
If you want a real Amiga, just go to a thrift store or flea maket and pick one up. OS4 runs on the SAM440 or a used AmigaOne, neither of which are real Amigas. If all you're interested in is an Amiga-like operating system (like OS4) you can pick up AROS for free.
