I have been promising to re-visit this subject for several months now. It was prompted by a series of articles in, errrr Decanter magazine.
Over 3 editions and countless pages it came to some broad conclusions. They tested various wines, vintages and decanted them over several set periods.
One example would be a Shafer from Napa with a Lynch-Bages from Bordeaux over three vintages 1996, 2000 and 2006. Then tasting immediately, then after one, two and four hours. To save you having to read all this info, the conclusions were pretty straight forward.
The answer is YES, do decant and one hour ahead is consistently good.
I did think about finishing the blog here as the simplest advice is often the best but there are one or two other pointers.
Decanting two hours ahead is good for younger wines.
Longer decanting periods are risky.
Very rich wines keep their freshness by being opened but not decanted.
A good half way house might be to open a wine an hour before serving, pour a little into a glass and taste immediately and then after 10 minutes. Depending on the taste you will know whether it needs decanting.