The Jargon File (version 4.4.7, 29 Dec 2003):

ubergeek
 n., /oo'ber?geek/

    [common; often spelled with initial ?; from German ?ber + geek] Almost
    synonymous with demigod; used as a compliment of someone regarded as a
    paragon of geek achievement and virtue. Has partially replaced earlier 
    demigod.