if you want to stick with the prostaff, for $10 more you can get a 3-9x40 here at clearance price.
Nikon 3-9x40 ProStaff Riflescope
personally, i'd probably buy one of these in 2-7x32 for a little bit more, as it is about 4 classes higher than the prostaff is.
SWFA Vortex Rifle Scopes Vortex Viper Rifle Scopes
and this is not my list, but is quite relatively accurate. best from top to bottom.
2009 Riflescope Rating Scale
Leica ER, Swarovski Z6, Zeiss Victory
Kahles C - CL & CSX, Premier Reticle, Schmidt & Bender
Kahles KX, U.S. Optics, Swarovski PH & American Lightweight
Bushnell Elite 6500, Leupold VX-7, Nightforce NXS, IOR Valdada, Vortex Razor
Bushnell Elite 4200, Leupold VX-3, Nikon Monarch & Monarch X, Zeiss Conquest
Leupold Mark 4 VX III & VX-L, Meopta, Nikon Monarch Gold & Titanium, Sightron SIII & S2 Big Sky, Vortex Viper
Burris Black Diamond Signature Select XTR & Euro Diamond, Pentax Lightseeker, Trijicon Accupoint, Weaver Grand Slam
Bushnell Elite 3200, Leupold VX-II, Millet Tactical/Buck Gold, Nikko Stirling, Nikon Buckmaster, Sightron SI & SII, Vortex Crossfire & Diamondback, Super Sniper Fixed
Burris Fullfield II & Timberline, Leupold Rifleman & VX-I, Leatherwood, Mueller, Nikon ProStaff, Simmons
Barska, Sightmark, Swift, Truglo
BSA, Tasco, Yukon
ATN, Leapers, NcStar