After Steve posted his suggested 60* temp, it got me wondering if there is a rule on standard temps for white wines in competition. All I got after a half hour of searching is - temps between 50 and 60* are normal for white wines and you should chill your wine to the temp you like best. Nothing on "what the rule is" in competition... So, I didn't find that terribly helpful.
Personally, I like my white wines chilled below 50*.