Possible acquisition is Siebel Systems (SEBL ), a specialist in customer-management software. Even SAP (SAP ) remains a possibility. Though the deal is officially off the table, some analysts believe talks could resume if Oracle eventually buys PeopleSoft, putting pressure on Microsoft's server business.The most intriguing and dramatic deal would be for services giant Accenture (ACN ). The company, which has a market cap of $24 billion, is a powerhouse in the lucrative consulting and business outsourcing arenas. Already there are affinities between the two companies: Ballmer sits on Accenture's board, and the two companies co-own Avenade, a boutique consulting outfit that specializes in Microsoft technology.