Safari 6.1 Suddenly Slowing MacBook Pro to a Crawl

Question

I know that it's risky to blame system problems on particular programs, but here I really fee like it's Safari.
In the past month or so I've been getting the spinning beach ball more and more often, and I can't tell you how many times I've had to Force Quit Safari.
Very rarely, it hangs the computer completely and won't even let me Force Quit anything.
I've repaired Permissions several time and verified my HD -- no problems.
Is there some particularly evil combination of some program interacting with Safari that's causing this? I really have not installed anything weird in the past few months but that spinning ball has become my nemesis!
Oh for the days of DiskWarrior or even good old Norton Utilities . . . I used to be able to defragment my drive with Classic but now it seems that you can't defragment your drive.
Here is a typical list of programs that will all be opened at the same time -- worst case scenario -- as Safari 6.1:
Photoshop CS 3
Mail
SpamSieve
Sometimes Preview
Some times TexEdit Pro
Sometimes iTunes
I'm running OS 10.8.5 on a standard Mid-2012 MacBook Pro bought refurbished from the Apple Store Canada.
Any ideas greatly appreciated!
Nick

Answer 1

Whatever you do, don't waste money on "Disk Warrior." It's completely useless if you have adequate backups, which you must have. If you don't have a current backup, back up immediately, before you do anything else. Ask if you need guidance.
When you see a beachball cursor or the slowness is especially bad, note the exact time: hour, minute, second.  
These instructions must be carried out as an administrator. If you have only one user account, you are the administrator.
Launch the Console application in any of the following ways:
☞ Enter the first few letters of its name into a Spotlight search. Select it in the results (it should be at the top.)
☞ In the Finder, select Go ▹ Utilities from the menu bar, or press the key combination shift-command-U. The application is in the folder that opens.
☞ Open LaunchPad and start typing the name.
The title of the Console window should be All Messages. If it isn't, select
          SYSTEM LOG QUERIES ▹ All Messages
from the log list on the left. If you don't see that list, select
          View ▹ Show Log List
from the menu bar at the top of the screen.
Each message in the log begins with the date and time when it was entered. Scroll back to the time you noted above.
Select the messages entered from then until the end of the episode, or until they start to repeat, whichever comes first.
Copy the messages to the Clipboard by pressing the key combination command-C. Paste into a reply to this message by pressing command-V.
The log contains a vast amount of information, almost all of it useless for solving any particular problem. When posting a log extract, be selective. A few dozen lines are almost always more than enough.
Please don't indiscriminately dump thousands of lines from the log into this discussion.
Please don't post screenshots of log messages—post the text.
Some private information, such as your name, may appear in the log. Anonymize before posting.