I've been wondering for a while now how far Sun would plummet before being acquired, and the answer is in. The wait is over wondering who might buy Sun. The answer is Oracle.
Oracle lacks expertise in selling hardware ... making its acquisition of Sun something of a joinder of like minds. Oracle has expertise running enterprise software on Sun's platform, however -- and allowing it to be potentially lost might work against Oracle's effort to project a stable future path for its customers who don't want to face the disruption of change. (Including, say, change to a Microsoft operating system offering a questionable security record.)
How Oracle positions its new operating system and hardware assets against those of vendors on whom Oracle has relied to resell Oracle products -- through the vendors' consulting businesses -- remains to be seen. If Oracle manages to alienate those with whom it is important to play nice, Oracle could find that its database software -- like Sun's operating system software -- is increasingly replaced with license-free alternatives that leave users more resources available for overseeing and improving implementation efforts.
My guess? Oracle's pre-existing expertise solving enterprise problems will keep it alive and well for a considerable time regardless what database might sit at the back end of its solutions, or how those databases might be priced.
I just don't see Oracle's purchase of Sun as clearly improving its competitive position -- though it might be said that preventing Sun from falling into the hands of a competitor might be a worthwhile objective in its own right.