For close in, Longs Peak is my favorite, however it is a long hike and there are some steep and narrow areas once you get past the Keyhole. Quandry is just Southwest of Breckenridge and is a fairly easy hike, just make sure you have a map and stay on the main trail. The drive to Quandry is about 2 hours from Denver and the views on top a spectacular. There are also Torreys and Greys peaks, they are a shorter drive, this side of the Eisenhower Tunnel. The road gets fairly rough a mile or so before the parking area, so cars can be hard to get up to the trailhead. But they are not too difficult to hike.
