Should i be ok with the thermal paste/pad that comes with a processor or should i buy Arctic silver. I currently do not over clock and do not have plans to over clock. But if i changed my mind and did over clock is it worth the while to use the arctic silver?

For a few extra dollars I would....
I would say without a doubt that its going to be better than what comes on it.

definetly get AS5 !

http://www.dansdata.com/goop.htm

That's all the info you need. If you're looking to squeeze every last Watt of power out as quickly as possible, then sure - go for AS5. If it's a stock system at stock speeds - you don't need to waste the money.