Is it just me, or were the early 90s a great time for kid's cartoons? You had Saturday morning cartoons about scifi war like ExoSquad or BattleTech, and then the Disney afternoon block with stuff like Duck Tales, TaleSpin, Gargoyles, and Darkwing Duck. And of course, we also had the Marvel animated series, namely the X-Men TAS, Spider-Man TAS, and Iron Man TAS. The funny thing is, all of those early Marvel shows have now had replacement series pop up. While I haven't watched these new millenium newcomers and can't comment on their content quality, I feel I am justified in saying that... well, the intros for the early 90s shows are far far superior. Just watch and be reminded of how fucking catchy those were.
X-Men TAS (1992): http://www.youtube.com/watch?v=s6KPt-QKDFU
Wolverine and the X-Men (2008): http://www.youtube.com/watch?v=juasmfRK-_w
Spider-Man TAS (1994): http://www.youtube.com/watch?v=x4w3kgoE_Cc
The Spectacular Spider-Man (2008): http://www.youtube.com/watch?v=2S19w2xXU54
Iron Man TAS (1994): http://www.youtube.com/watch?v=lfWPDzvWNds
Iron Man Armored Adventures (2008): http://www.youtube.com/watch?v=yr0AAqRxwBQ