I'll echo the 2.5-10x mag range recommendation. A lightly used Nightforce 2.5-10x32 would be hard to beat for the $1000 ish price point.
The 32mm Vortex PST would be great as well. The new Burris XTRII's are worth a look. The 1.5-8x would be a great M1A setup also.
For value, the SS 3-9x42 is a favorite at around $600. Weaver Tactical has a 2-10x36 worth mentioning too. Leupold VXR patrol is a nice scope, if you can handle the reticle thickness; the illumination system is nice and daylight bright.