Scope Zoom

What power zoom (on a spotting scope) is recommend for a 300 yard target and a 500 target?

my target range is only 100 yards and i just use a cheap simmons 24 power spotting scope. i have never seen any over 76 power and the price was still reasonable. around $ 120 from sportsmans guide magazine. but that was a generic brand. im sure good companys like zeiss or leupold make alot better.

Sony Vegas Pro 9- MW2 Scope Zoom Transition Tutorial