A great choice would be Marvel Team-Up Vol. 1.

It starts a new line, as did #'s 50 and 100.

All included issues would feature Marvel's flagship character, Spider-Man.

It also includes a nice sampling of the Marvel Universe, with appearance by the original X-Men, two of the Fantastic Four, Iron Man (whose new movie will almost assuredly be out on DVD at that time, for holiday sales), Thor (whose movie will be in theaters a few months later), and others.