This surely won't be for everyone, but the samples I've heard from this compilation of covers show that Campbell hasn't lost his vocal chops, and his sincerity transforms this project from schtick (see Pat Boone) to something more valuable.

[ame="http://www.amazon.com/Meet-Glen-Campbell/dp/B001BOMBSS/ref=pd_bbs_sr_1?ie=UTF8&s=music&qid=1219862629&sr=8-1"]Meet Glen Campbell[/ame]