The Spin Offs

[Stu]

Now then

The Marvel cartoons of the 90's (more or less) where a single continuity, and because of it, we had guest stars show up in all of the series, sometimes, as a cross promotion type event, like in Helping Hand Iron Fist and The Mutant Agenda.

But a lot of the guest stars are there to act as a pilot style episode for a new character. We had a few of these.

Spider-Man And His Amazing Friends - The X-Men Adventure
Hulk - Inncocent Blood (Ghost Rider)
Fantastic Four - Various Silver Surfer apperances
Spider-Man - Guilty/The Man Without Fear
Hulk - The Thor episode

There are numerous others, which of them do you think would've been a great stepping stone to another series?

[HellCat]

I think DareDevil and Morbius/Blade/Black Cat from Spider-Man could have easily lead into spin-offs. DD left saying he had something to work on out of town and was leaving the job of keeping an eye on the Kingpin to Spidey. A series could have followed his adventures outside of NY then bring him back and eventually team him up with Spider-Man again.
As for the vampire hunters- Something similar to Angel with the 3 of them tackling various supernatural foes whilst trying to find a cure for vampires to help Morbius, Blade and his mother.

I'd say FF Silver Surfer would be the worst lead in for a spin-off. In season 1 he was a wimp who couldn't shut up about how great humans and Earth were. In season 2 he did a 180 and was moaning about how much being on Earth sucked. The short lived TV show was wise to ignore this take on the Surfer.