my opinion is it doesn't make a practical difference and there is no point paying for something else. just use whatever comes stock. unless it doesn't come with any at all.
And if it doesn't, most computer stores sell the Arctic Silver for well under 10 CDN dollars, usually around 5 - at least here, in Ontario
Edit: Just checked, and it looks like that cooler comes with half-decent thermal paste already, so I would just use it. Also, It appears I may have been wrong about the Arctic Silver 5, newegg lists it at 25$... It appears I'm thinking of straight Arctic Silver which lists at
8.99 7.99, not Arctic Silver 5