I think people need to stop thinking of the current tablets as being desktop replacements. There will be files that can't run on every device I see coming out in the near future. If I send a Playbook owner an ALAC or Flac file, they can't play it. While that may be a disappointment, it is just a fact of life. Personally, I use ALAC a lot more than flash.
I don't think the iPad works as a great first or only computer. You also need a computer for updates, backups, syncing, etc...
Personally, if the iPad had been a full scale computer, I would not have bothered with it. I wanted something similar to my iPhone with a much larger screen for running apps, reading, web surfing, etc.. I actually like iOS.
For me, it has become my 70% MacBook Pro replacement