Getting 'Flash' 'Running'

Sorry for the quotation marks, but it's not really Flash, but rather an open source version, called Gnash, that you will be 'running.'  Yeah, the quotation marks around 'running' are important too.  Remember that the Pi is not a very powerful machine, and any Flash heavy page is going to bog it down - especially since most browsers already max out the Raspberry's CPU and RAM.  You certainly won't be able to use it to watch Youtube videos.  :(  If you still need to run Flash, for whatever reason, here's how.

Step 1:  Type the following into the terminal:
sudo apt-get install browser-plugin-gnash

Step 2:  You will need to restart the browser (if you have it open).

You can now play (very simple small) Flash Games and view annoying advertising.  Congrats!  :)

Surfing the Web

Not something the Pi does well, but it can still be improved.  Firstly Midori is not a bad browser, but Iceape will probably be better.  It is less intensive, and has an adblocker which is pretty damn handy given the state of the web these days.  You can even switch off java and images to save bandwidth / processing power.

Step 1:  sudo apt-get install iceape

That's it, iceape is now installed.  I recommend the adblockplus plugin as a bare minimum

Step 2:  Go to 'Tools>Add-ons Manager and search for adblock.  When it comes up click on the install button.  You'll need to restart the browser to make it work.

If you think you'll need flash then I recommend gnash (an open source alternative):

Step 3:  sudo apt-get install browser-plugin-gnash
Don't try and view / play anything too big though - the RPi's not built for it.  Youtube is still a big fail.  Sorry.