Cool Comic Sites

The World

Marvel (The official website of Marvel Comics)
MarvelWikia (Marvel Comics Database)
comicbookdb (The fastest-growing comic database on the web)
Comic Book Realm (Database for your comic book collection. Good site to get an idea what your comics are worth.)
ComicsPriceGuide (Good site to find out the value of your comics)

Fansites

Uncannyxmen.net (A great site about the x-men)
The (almost) complete Marvel crossover guide (If you love crossovers. This is the site to visit. It is simply AMAZING.)
Comics Back Issues (Reading order of X-Men comics since 1963, graphic timeline and much much more)

Comic-shops

Milehighcomics (The world largest comic shop)

Denmark

Danske tegneserieskabere (Newsmedia about Danish comics and comics artists)
ComicWiki  (Danish wikipidea about comics)
Troldspejlet (Entertainment about games, comics and books – known from DR – danish television)

Fansites

Superhelteserier (Denmarks largest Marvel and DC database)
http://www.bbsyd.dk/tegneserier/index.html (A Marvel-enthusiast like me – many Marvel comics for sale both Danish and American)
mrjonesbond (Another Danish Marvel-enthusiast with American Marvel comics for sale.)

Comic-shops

Fantask (My favorite comic shop in Denmark. I have all my Marvel Comics subscriptions here)
Faraos cigarer (Another great comic shop from Copenhagen as Fantask. The shop has many back issues of Danish comics)
Pegasus (Comic shop also from Copenhagen with a big selection of back issues of Danish comics)
Serie-boden (Web shop with many older Danish comics)