Definitely dont pay your mortgage. You could put it all in silver, but i'd put some of it into advertising costs because now is the time to gain market share in any business.
What is your true passion? Build a business around that... even if it doesnt look like it could make money (trust me, if you can grabs peoples attention, you can make money).
To be more precise, I started a website about something im passionate about (trance music and culture) in December 09 as a personal blog about trance related things i liked... then somehow it turned into a business this year

and im starting to see the infinite levels I can take that business to, how i can monetize it, how i can use it to start new businesses in the same industry etc...
For my industry, the best advertising I have used (and am still using) is facebook ads for pages. Im getting around 400-500 likes per day at the moment for only $6 per day. I made a landing page on facebook so that people who click on my add land here:
http://www.facebook.com/www.TranceMix.org?v=app_4949752878 so not only can i send information to their news feed, or updates section under messages, i can also build a double opt-in email list (thanks to feedburner) and boost my iTunes ranking (thanks to that iTunes button

)
I would put 30k in facebook advertising for your dream business over whatever time-period you choose. Then put 50k in silver... as your savings

. I bought silver on August 17th and it has been averaging a 15% ROI per MONTH, not annum, MONTH. Thanks to governments printing dough... and with the inflation race starting, its only going to go up.
Dont pay the mortgage... thats the kind of thinking that employees and poor people have. You can get a return that is higher than your mortgage repayments just by investing in silver.
I use
http://silver.bullionvault.com because when you buy silver from them, you actually own the silver, it is stored in a London vault which is fully insured. $50,000 of silver would be a bitch to store yourself... and pointless when bullionvault can take care of that for you.