Don't be so quick to dismiss this rumor guys. As a former IBMer, let me share a view pieces of recent Big Blue lore:
1) IBM came THIS|CLOSE to buying Dell in the summer of 1999. It would have happened if IBM's stock hadn't hit a plateau while Dell's continued to soar. By October 1999, the Dell strike price that was on the table in May had already been exceeded by 15 percent. IBM briefly considered buying Gateway or Micron PC, but decided they were heavily overvalued.
2) Apple fits the IBM strategy better than Dell. Apple has done something almost no other PC manufacturer has been able to accomplish -- maintain its margins. That's music to IBM's ears.
3) IBM loves UNIX. Within three years, every IBM OS will be UNIX based. They are making massive LINUX investments. OS X is a very nice fit for them.
The final, important part of the puzzle is Apple's share price ... the company is seriously undervalued. It has a ton of cash, loyal customers, great margins ... there's nothing for IBM NOT to love. Plus it's the only serious MS competitor.
The big negative, of course, is culture. These two cultures cannot be reconciled. Apple will need to be left alone ... and IBM is terrible at that. They always talk a good game about leaving Lotus or Tivoli to do their own thing, but when push comes to shove, they're right back to their old monolithic.
In conclusion, this would be a great move for IBM ... but I hope it doesn't happen.