Most likely you won't be eligible for a free* (*US$19.95 s/h fee) upgrade to Tiger. When they announced the last OS X upgrade (Panther) only people who bought systems on the day of the announcement or later were eligible for the free* upgrade.

As far as Safari goes, the animated GIF problem is the whole page is forced to reload for each frame of the GIF animation. This is why Safari bogs down when animated GIFs are on screen. This will peg the CPU on just about any Mac available today.

To see this in action, open the CPU monitor (or alternatively, run 'top' in a terminal window). Then open a page with many animated GIF files (the post page for this forum works nicely). Now, scroll the animated GIF portion off screen (shrink your Safari window if necessary). See how low the CPU usage is? Now, scroll the animated GIFs back onscreen and watch the CPU start smoking from working so hard! Scroll the GIFs back off screen again so you can see the CPU usage diminish back to normal levels.

This problem has been fixed in the Tiger builds of Safari, at least from what I've heard. I don't have a copy of Tiger so I'm not breaking any kind of NDA or what have you in relating this information. (The preceding announcement brought to you by the words 'Law' 'Suit' and 'Apple' )