About Lord Ganesha, it is said-एक दंत दयावंत चार भुजाधारी, here चार भुजाधारी means chaturbhuj. And so it Lord Vishnu who has four arms and one of his arms has Sudarshan Chakra.

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Note added at 2 hrs (2008-03-22 07:28:53 GMT)
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But in Hindu mythology chaturbhuj is specially use for Lord Vishnu.

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Note added at 2 hrs (2008-03-22 07:41:45 GMT)
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Lord Vishnu has 1000 names and one of these is chaturbhuj. There is चतुर्भुज, विष्णु, मंदिर in धमधा, दुर्ग. Also see-विhttp://tdil.mit.gov.in/CoilNet/IGNCA/chgr0019.htm विष्णु का विग्रह सिंहासन पर स्थित है। यह प्रतिमा काले पत्थर की बनी विष्णु की चतुर्भुजी मूर्ति है। जिसके हाथों में शंक, चक्र, गदा और पदम है जिसकी लोचन के नाम से पूजा होती है। You can also have a reference of chaturbhuj in the following shlok of Geeta- किरीटिनं गदिनं चक्रहस्तमिच्छामि त्वां द्रष्टुमहं तथैव ।
तेनैव रूपेण चतुर्भुजेन सहस्रबाहो भव विश्वमूर्ते ॥ ११-४६ Here chaturbhuj means चतुर्भुजेन रूपेण = चतुर्भुज विष्णु रूपात. For this kindly see http://mr.wikibooks.org/wiki/श्रीमद्‌भगवद्‌गीता_:_अकरावा_अध्... So the actual answer is Lord Vishnu.

There numerous deities in Hindu mythology who have four or eight arms. Based on whatever little exposure I have had to hindi scriptures translated into English I am confident of validity of my suggestion here. The reason for my confidence is that the phrase "the four-armed one" is generic enough to fit to any mythological figure having four arms.