Flash is no longer supported we are stuck on 11 but we still get security updates.
That's true, if one runs Firefox or Seamonkey in their Linux.
If one runs Google Chrome, be it Linux or Windows, one always has the latest Flash built into the browser. One reason why a few Linux versions has Chromium (open source version of Google Chrome) as their default browser. Most extensions that works with Google Chrome does on Linux versions, and any profiles created on Windows will roll over to Linux, just sign into the browser. That also works with Firefox & some rebranded Linux versions of the browser, though Firefox Sync is a lot slower than that of Google, regardless of the OS.
And to answer Stolen's question, browsing is no different on Linux, though even faster due to less overhead, there's just no IE. That may be a good thing, though there are now adblocking options with IE, the same Adblock Plus that's modified, and Web of Trust (WOT) is also available, but they have to be downloaded from IE. Though one has to disable Enhanced Protection Mode for these extensions, actually it's an automatic process.
What I don't like is the few times when I do have to open IE to get software for Windows, every time it's opened, in essence, it's asking one to disable extensions to speed up the browser. If I was concerned about speed, would certainly not be using IE, and am glad that MS years ago seen the light & quit delivering updates through the browser. I have been tempted to disable IE through the "Turn Windows features on or off", but got a warning every time that certain services may not work.
Other than possibly Mail, what wouldn't work if IE were disabled? Every time I run Windows, even though normally never use IE, there's a moderate amount of files from the browser to be deleted from that session, as running CCleaner is the next to last thing I run before shutting down. A quick scan with SuperAntiSpyware is the last, to clean the normal places where ad/tracking cookies hides.