IIRC on the pitch (obviously other factors and big punishments soon came into play), the title races between Capello's Juve and Ancelotti's Milan in 2004/2005 and 2005/2006 were very exciting and high quality. In 2004/2005, the teams were level on points with a few games left and going into a huge title showdown at the San Siro. Juve won it 1-0, and Milan's domestic form then collapsed. In and around that period, they were pretty terrible against PSV in their 2 semi-final matches as well. The first 45 minutes against Liverpool was probably their best performance of the final stretch of that season by a long way, but being in contention to win both the CL and the Scudetto and missing out on both would have stung a lot.
In 2005/2006, they ended the season in outstanding form, winning something like 13 or 14 out of their last 15 or 16 games, narrowing Juve's previously big lead (I think Juve suffered a hangover after their CL exit against Arsenal) significantly, finishing 3 points short with a total that in most seasons would have been good enough to win the title. Of course Juve and Milan both received big punishments and Inter were awarded were that title (it really should have been left vacant like the 2004/2005 one). In their CL semi-final 2nd leg against Barca, a goal from Shevchenko was controversially (to put it mildly) disallowed.
So they were in serious title contention 3 years in a row, but the fallout from Calciopoli and as you said an ageing squad that wasn't sufficiently freshened up ended that.
I remember in 2002/2003 after Milan's impressive performances during the CL 1st and 2nd group stages, there was talk about how they were 'back'.
