If you're willing to do some Internet Detective Work, you can also find out about earlier trades that have been out of print for the last 15 years, such as
The Origin of the Hobgoblin - my favorite
The Saga of the Alien Costume
Nothing can stop the Juggernaut (yes, it's a Spider-man trade, not X-Men)
I think they did a couple on the Sinister Six stories from the 1990s, but I'm not sure.
Hobgoblin Lives
Spider-man/Human Torch (LOVED the Spider-mobile issue, particuarly the ending, and how they beat the villians of the story).
Oh, wait, here's a more or less compiled list:
http://tplist.millarworld.net/spiderman.html (missing the juggurnaut trade for some reason)
Avoid Kraven's Last Hunt though. Of course, while popular, I hate it with the passion of a thousand fiery suns, but to each his own.