Patience pays off. Downloaded Firefox 3 this afternoon with no trouble. Install went smoothly and all is well. The “awesome bar” worked well since my open tabs before the upgrade did not get restored after the installation.
Memory usage, at a quick glance, looks better than Firefox 2. Random and most non-scientific comparison between Firefox 3 and IE 7 with same set of tabs open and both playing a TED video of BumpTop shows Firefox using slightly more memory but at least half the CPU of IE.